xmerge: The assigned value is never used

Change-Id: I1c9730d494546b01836c60f49861784a068ca1a0
Reviewed-on: https://gerrit.libreoffice.org/10660
Reviewed-by: Noel Grandin <noelgrandin@gmail.com>
Tested-by: Noel Grandin <noelgrandin@gmail.com>