[BUGFIX] Handle all exception cases in the Doctrine connection (Revision 1)

Now all cases of an exception are handled and given through in case
a PDO exception occurs.

Change-Id: Ia5ad826cda0e26e5e7ae27cbe2a29110187c539d
Releases: 2.1
Revision-Id: f28ff6c014a901775c80214f9c0e79528bdebc32