The change to sal/log.hxx affects extensions too which are not required
to use a C++11 compiler.

Change-Id: I3ed08f9a02a2e082fcdb821bce84244597f2390a
(cherry picked from commit f168fcae)
Reviewed-on: https://gerrit.libreoffice.org/17502Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>