oC crash with CAS app and Encryption enabled.

[cburnard]

Steps to reproduce

Turn on and confirm encryption in ownCloiud 8.2.1 using "enable-master-key". Then add CAS app to their ownCloud server.

Expected behavior

ownCloud loads webpage fine and produces no errors.

Actual behavior

ownCloud returns blank screen wihen CAS is enabled. Disabling the CAS app returns the server to normal with encryption.

{"reqId":"eQtCF8fRHil9E+Ukvkq5","remoteAddr":"x.x.x.122","app":"PHP","message":"Undefined index: cn at \/var\/www\/owncloud\/apps\/user_cas\/lib\/hooks.php#51","level":3,"time":"2015-12-21T11:30:54-08:00"}
{"reqId":"eQtCF8fRHil9E+Ukvkq5","remoteAddr":"x.x.x.122","app":"PHP","message":"Undefined index: mail at \/var\/www\/owncloud\/apps\/user_cas\/lib\/hooks.php#56","level":3,"time":"2015-12-21T11:30:54-08:00"}
{"reqId":"765Lh3cM1MD0h91OSRPp","remoteAddr":"x.x.x.123","app":"PHP","message":"Undefined index: cn at \/var\/www\/owncloud\/apps\/user_cas\/lib\/hooks.php#51","level":3,"time":"2015-12-21T11:31:25-08:00"}
{"reqId":"765Lh3cM1MD0h91OSRPp","remoteAddr":"x.x.x.123","app":"PHP","message":"Undefined index: mail at \/var\/www\/owncloud\/apps\/user_cas\/lib\/hooks.php#56","level":3,"time":"2015-12-21T11:31:25-08:00"}
{"reqId":"VAd+QWw3lybwQz+0YAYV","remoteAddr":"x.x.x.123","app":"PHP","message":"Undefined index: cn at \/var\/www\/owncloud\/apps\/user_cas\/lib\/hooks.php#51","level":3,"time":"2015-12-21T11:31:41-08:00"}
{"reqId":"VAd+QWw3lybwQz+0YAYV","remoteAddr":"x.x.x.123","app":"PHP","message":"Undefined index: mail at \/var\/www\/owncloud\/apps\/user_cas\/lib\/hooks.php#56","level":3,"time":"2015-12-21T11:31:41-08:00"}
{"reqId":"E3t9mh\/iBFO9anA8zSAX","remoteAddr":"x.x.x.123","app":"PHP","message":"Undefined index: cn at \/var\/www\/owncloud\/apps\/user_cas\/lib\/hooks.php#51","level":3,"time":"2015-12-21T11:34:24-08:00"}
{"reqId":"E3t9mh\/iBFO9anA8zSAX","remoteAddr":"x.x.x.123","app":"PHP","message":"Undefined index: mail at \/var\/www\/owncloud\/apps\/user_cas\/lib\/hooks.php#56","level":3,"time":"2015-12-21T11:34:24-08:00"}

Server configuration

Operating system:
Ubuntu 14.04
Web server:
Apache 2.4.16
Database:
MySQL
PHP version:
PHP 5.59
ownCloud version: (see ownCloud admin page)
oC 8.2.1
Updated from an older ownCloud or fresh install:
Fresh