That python bug cause problems when libreoffice is on a read-only
media... which is very common for Mac as the dmg used to package
the produce is seens as a read only volume.
This patch the bug 15833 for MacOSX only since that is the platform that
is most likely to be impacted, and because of bug 15431 that make
patching on Windows more complex/dangerous.

Change-Id: Ie7406c1c75748d38c871b3b544560caa62e9d838
Reviewed-on: https://gerrit.libreoffice.org/1934Reviewed-by: Norbert Thiebaud <nthiebaud@gmail.com>
Tested-by: Norbert Thiebaud <nthiebaud@gmail.com>