Update marconi.conf-sample to deprecate sqlite

Now we're supporting sqlalchemy and the sqlite is deprecated.
So the marconi.conf-sample should be update to reflect the
change so as to avoid confusion.

Closes-Bug: #1288619

Change-Id: Ief5dad6345dc24e70af18e9e47d0f8dd384cee47
Slighty refactored url_prefix usage in WSGI tests

Several calls to url_prefix has been replaced
with the usage of a common variable in WSGI tests
in order to adjust to DRY principles.

Change-Id: I056e1e8879a97f6a30aff924e55bdf50897c08e4
Closes-Bug: #1285219
Enable shards test for sqlalchemy

Now we have already implemented the sqlalchemy for shards and
catalogue, so this patch will enable the shards test for
sqlalchemy.

Closes-Bug: #1288148

Change-Id: I1bc96419f2525d5211448d68c8c871dda14535a7
Merge "Slighty refactored url_prefix usage in WSGI tests"
Merge "Update marconi.conf-sample to deprecate sqlite"