ncm-network: nmstate - down the interface connection before applying

nmstatectl apply does not replace running config instead it seems to append.
This is not useful when settings have been removed such as policy routing.
Therefore down the interface connection during configuration changes.
This will be now similar to original main ncm network module where it runs ifdown and ifup during config changes.

ncm-network/src/main/perl/nmstate.pm

@@ -518,6 +518,8 @@ sub nmstate_apply
             # apply config using nmstatectl
             my $ymlfile = $self->iface_filename($iface);
             if ($self->any_exists($ymlfile)){
+                $self->verbose("Apply config for inteface $iface");
+                push(@cmds, [$NMCLI_CMD, "conn", "down", $iface ]) if $self->is_active_interface($iface);
                 push(@cmds, [$NMSTATECTL, "apply", $ymlfile]);
                 push(@cmds, [qw(sleep 10)]) if ($iface =~ m/bond/);
             } else {