renamed env variables to DEFAULT_DB_URL and added OTHER_DB_URL
postgres database url in .travis.yml
sqlite trvavis db url
Use socket for database connection.
Decrease verbosity because logs are too big.
Only runna da failing tests.
Revert "Only runna da failing tests."

This reverts commit f9eb47d5cb68dffcccb9ac5db8751df9fcd17764.
Disable memcache momentarily.
Fixed regression from #17083 -- settings_override.

As settings_override was used after the 
initialization of the session backend, we need to
use a new session backend here.
Revert "Disable memcache momentarily."

This reverts commit acadbff3ab221209e213495ec021b9a713ee18ba.
Merge commit 'b70929f20476e3ddfaae067ecced5a62f733209c'