Fix bug in test_signercli.py and update test case following PyCrypto changes

A bug in test_signercli.py prevents required keys from loading.  A password for a test keyid is modified but not properly restored.  This particular bug made it difficulty in adding a new feature (i.e., derived keys) and updating the unit tests.  We need to simplify the unit tests, specifically the removal of side effects, monkey patches, pseudo repositories/data structures, and dependency on scripts that expect user input.  'signerlib.py' should be called instead of the signer tools (e.g., signercli.py).