Don't test EOL cinderlib branches

cinderlib stable/ussuri went EOL with change I75092342fe68.
cinderlib stable/train went EOL with change I25d78267ab4a.
Revise the cinder-tempest-plugin-lvm-barbican-base job for
these branches so that they don't run the cinderlib functional
tests.

Change-Id: I2c66fcb64ffe1ac4a03778e7a11c67fbd20166ba
1 file changed