adjust magic binary index that identifies the theme name res id

because libreoffice inserted a bunch of extra resources since fork point.

We should get rid of these ids entirely and e.g. at least instead use the
filename number as the the id instead which would be a little less painful.

Change-Id: I5d0a3b5e60dbe448164bdff25d46171a1ed4d55e
(cherry picked from commit 8e9bcdb73adf7b544299bb57fcce5423b43cc058)