specfile: Use python-2.6 installdirs on rhel 5 compatibles

Since we require python26 for everything 'mon'-related to work
properly, we need to put livestatus' python libraries in the
python 2.6 paths.

This fixes issue #6725.

Signed-off-by: Andreas Ericsson <ae@op5.se>
spec: fixed typo, it's called monitor not monitorB

would that be a lesser quality monitor?

Signed-off-by: Mattias Ryrlén <mattiasr@op5.com>