Redirect stderr to /dev/null when running setup.py --version
Redirect stderr to /dev/null when running setup.py --version

In some rare cases (os-faults in fedora, for example), we see ouptut
sent to stderr, which confuses the setversionandrelease function.

Change-Id: I965452e14b66188a543c53d02a18e39cf8938ffe

openstack-packages/delorean,openstack-packages/delorean,openstack-packages/DLRN,openstack-packages/DLRN