Fixes potential reliablity issue with missing CONF import

Adds missing CONF.import lines for the keys_path
config option in crypto.py. Although the code currently
appears to work fine, missing import options can result
in flakey unittests and so most likely problems in real
Nova setups as well.

Change-Id: I748a47ecf6b6f0a2ff14db2bcd402163fc0b011e
Merge "Fixes potential reliablity issue with missing CONF import"