Call get_pgsql_connection_info from _test_postgresql_opportunistically

The _test_postgresql_opportunistically method was calling the method to
parse the mysql connection URL which is wrong when there is one
specifically for postgresql, so call the right method.

This wasn't causing issues obviously but is something that needs to be
cleaned up regardless.

Closes-Bug: #1274718

Change-Id: Ic572e612c7ce31d854dc7258aa9c8b89a197260e
Make error notifications more consistent.

The error notifications sent by wrap_exception are a good source of
information when tracking down errors in the system. It is easy to spot
patterns in the errors by looking at similarities in the exceptions
raised.

This change looks at making the in-line error notifications
follow the same format, so they become equally useful.

Closes-Bug: #1251602
Change-Id: I1cd64a90ecefc64d12af05487eb6e45aa0362d69
Merge "Call get_pgsql_connection_info from _test_postgresql_opportunistically"