IMDeleteSurrounding is used by input methods to take multiple
keystrokes and convert them into a special character.  Then the
composing keystrokes are removed.
Before this fix, the cursor placement was not adjusted,
so the special character was inserted in the wrong position
and if 3+ keystrokes were involved, the wrong characters were deleted.

Change-Id: I35b97bc150dc68ffe65eebc59450e21e0033bd16
Reviewed-on: https://gerrit.libreoffice.org/15961Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>