build: Fix %install on < F20

The setup.py script always installs documentation into an unversioned
doc dir so adjust the spec file to look in the right place when
manually installing files.

Change-Id: Ia6aaea13996675b12f3ccc8c8e5eeda6a278ca57
Signed-off-by: Adam Litke <alitke@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/23146