Add to calendar instead of replacing, when importing

[mdavis-xyz]

Steps to reproduce

Click Settings > Import Calendar

Expected behaviour

Back in the older version where you had to import calendars from the file browser, when selecting which calendar to import the ics file to, you could choose to either delete all the events in the calendar and start fresh, or add to all the events in the calendar. I want both options.

Actual behaviour

There is no choice.
There is not even any text informing the user that if they import an ics into an existing calendar, everything currently in that calendar will be deleted.

Server configuration

Operating system: Debian 8.5 Jessie

Web server: Apache 2

Database: MySQL

PHP version: PHP 5.6.20-0+deb8u1

ownCloud version: 9.0

Calendar version: 1.2.2

Updated from an older ownCloud or fresh install: Updated

Signing status (ownCloud 9.0 and above): What does that mean?

Login as admin user into your ownCloud and access 
http://example.com/index.php/settings/integrity/failed 
paste the results here.

For the above, I see nothing. My browser shows a blank page. Not an error page. Just white.
My OC is at example.com/owncloud. I tried

• http://example.com/index.php/settings/integrity/failed
• http://example.com/owncloud/index.php/settings/integrity/failed
• http://example.com/owncloud/settings/integrity/failed

The debugger console in my browser says the following when I try to visit that link:

Load denied by X-Frame-Options: https://www.mdavis.xyz/owncloud/index.php/settings/integrity/failed does not permit cross-origin framing.

List of activated apps:

Enabled:
  - activity: 2.2.1
  - calendar: 1.2.2
  - comments: 0.2
  - contacts: 1.3.1.0
  - dav: 0.1.6
  - documents: 0.12.0
  - federatedfilesharing: 0.1.0
  - federation: 0.0.4
  - files: 1.4.4
  - files_mv: 0.8.2
  - files_pdfviewer: 0.8.1
  - files_sharing: 0.9.1
  - files_texteditor: 2.1
  - files_trashbin: 0.8.0
  - files_versions: 1.2.0
  - files_videoplayer: 0.9.8
  - firstrunwizard: 1.1
  - gallery: 14.5.0
  - notifications: 0.2.3
  - ownnote: 1.08
  - provisioning_api: 0.4.1
  - systemtags: 0.2
  - templateeditor: 0.1
  - updatenotification: 0.1.0
Disabled:
  - encryption
  - external
  - files_external
  - user_external
  - user_ldap

The content of config/config.php:

{
    "system": {
        "instanceid": "ocgpligctmz2",
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "10.1.1.200",
            "www.mdavis.xyz",
            "mdavis.xyz"
        ],
        "datadirectory": "\/media\/Maxtor\/owncloud",
        "overwrite.cli.url": "http:\/\/10.1.1.200\/owncloud",
        "dbtype": "mysql",
        "version": "9.0.2.2",
        "dbname": "owncloud",
        "dbhost": "localhost",
        "dbtableprefix": "oc_",
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "logtimezone": "UTC",
        "installed": true,
        "mail_from_address": "beaglebone",
        "mail_smtpmode": "php",
        "mail_domain": "mdavis.xyz",
        "forcessl": true,
        "appstore.experimental.enabled": true,
        "theme": "",
        "loglevel": 2,
        "maintenance": false,
        "trashbin_retention_obligation": "auto",
        "updatechecker": false,
        "singleuser": false,
        "memcache.local": "\\OC\\Memcache\\APCu"
    }
}

Are you using external storage, if yes which one: local USB hard drive

Are you using encryption: no

Are you using an external user-backend, if yes which one: I don't know what this means, so I guess that's a no

Client configuration

Browser: Firefox 47.0

Operating system: Linux Mint 17.3

CalDAV-clients: Thunderbird 38.8.0 with Lightning 4.0.5.2, CalDav Sync Adapter (Android)

Logs

ownCloud log (data/owncloud.log)

{"reqId":"tNyWXOgPjLh9TcY4h31E","remoteAddr":"10.1.1.2","app":"PHP","message":"Undefined offset: 0 at \/var\/www\/owncloud\/lib\/private\/appframework\/http\/request.php#700","level":3,"time":"2016-02-07T10:01:44+00:00"}
{"reqId":"tNyWXOgPjLh9TcY4h31E","remoteAddr":"10.1.1.2","app":"PHP","message":"fopen(\/var\/www\/owncloud\/config\/config.php): failed to open stream: No such file or directory at \/var\/www\/owncloud\/lib\/private\/config.php#191","level":3,"time":"2016-02-07T10:01:46+00:00"}
{"reqId":"bGtnGf30MR0XctpWoy0c","remoteAddr":"10.1.1.2","app":"PHP","message":"Undefined offset: 0 at \/var\/www\/owncloud\/lib\/private\/appframework\/http\/request.php#700","level":3,"time":"2016-02-07T10:04:02+00:00"}
{"reqId":"PgUCF3KMcARqC+gyrFi5","remoteAddr":"10.1.1.2","app":"PHP","message":"Undefined offset: 0 at \/var\/www\/owncloud\/lib\/private\/appframework\/http\/request.php#700","level":3,"time":"2016-02-07T10:06:21+00:00"}
{"reqId":"UXTOFkw7kQlJfxGObX0O","remoteAddr":"10.1.1.2","app":"PHP","message":"Undefined offset: 0 at \/var\/www\/owncloud\/lib\/private\/appframework\/http\/request.php#700","level":3,"time":"2016-02-07T10:07:04+00:00"}

[georgehrke]

Nothing is deleted when you import an ics into a calendar.

Dialog thing is a dup of #326