Resolves: fdo#69925 Wiki Publisher Extension is not working

Regression from http://cgit.freedesktop.org/libreoffice/core/commit/?id=b80d8c695e6b6ded231e67ed9a80bcd1f1250c03
"compareTo" has been replaced by "==", so we compared the equality ot the pointers on the objects instead of the content of the strings
To make it simple and since we compare String objects, let's simply use "equals" method

Change-Id: I65bc1a87751297411fdbe722d3f49bce5e291638
Reviewed-on: https://gerrit.libreoffice.org/8133
Tested-by: Michael Stahl <mstahl@redhat.com>
Reviewed-by: Michael Stahl <mstahl@redhat.com>