Adding a test case to expose a bug in snapshots

We made some changes bu is our service working correctly? Our previous test case passed but it worked with an empty database. Now we will extend our tests with a new case.

We will import our config file and the psycopg2 module into the test suite and modify setUp
to include initialization of a psycopg2 database connection and a cursor out of it.

We will also modify the tearDown method to close the connection after the test finishes.

Note this change will impact all test cases being run - even if they don't utilize the connection it will be established and closed upon each test.

Next we will add a new test_snapshots_fake_entries in which we will insert directly into the database
using our new connection. We have to commit the changes after each snapshot entry because postgres will set the created_at field to a time dependent upon when the changes were committed. If we do a single commit all the timestamps will be the same for our new entries.

Running the new test case exposes that the return value is in a different format then expected:
twisted.trial.unittest.FailTest: not equal:
a = [[u'fake3.png'], [u'fake2.png'], [u'fake1.png']]
b = ['fake3.png', 'fake2.png', 'fake1.png']

shutter.test.test_shutter_jsonrpc.ShutterJSONRPCTestCase.test_snapshots_fake_entries

The values returned by txn.fetchall() are additionally nested.