Specify postgresql version on Jenkins slaves.

The fact built into the postgresql module cannot determine which version
of postgresql to use in all cases (eg on Oneiric hosts). To get around
this hardcode the version to '9.1' when a default is not found by the
upstream module.

Change-Id: If5e4e0d7325d1507353d907cab4539260c7d4bc0
Reviewed-on: https://review.openstack.org/20196
Reviewed-by: James E. Blair <corvus@inaugust.com>
Reviewed-by: Jeremy Stanley <fungi@yuggoth.org>
Approved: Clark Boylan <clark.boylan@gmail.com>
Tested-by: Jenkins
Increase puppetlabs-apt to 1.1.0.

* install_modules.sh: The puppetlabs-postgresql 2.0.1 module wants
puppetlabs-apt 1.1.0, so this should stop the schizophrenic cronspam
from repeated failed attempts to install the old version.

Change-Id: Idad5951bb7b5c941a5239a4f20b80a90ee65ac1a
Reviewed-on: https://review.openstack.org/20257
Reviewed-by: Paul Belanger <paul.belanger@polybeacon.com>
Reviewed-by: James E. Blair <corvus@inaugust.com>
Approved: Clark Boylan <clark.boylan@gmail.com>
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Tested-by: Jenkins