fix irods pid check
add irods-specific changes to the unittest

because the irods backend makes more use of flask components,
we have to extend the TestStorageApi tests.

1. execute the tests with a request_context(),
  not only the app_context()
2. patch an irodsstorage method to get authentication details
  My attempts to patch flask.request have failed, so I
  introduced a method _get_authentication in irodsstorage,
  which is then patched.
fix disconnecting from irods when auth has failed

before irods connections for failed attempts
were not disconnected
fix running the irods unittests

1. fix an issue with the StorageApi test that
  teardown methods were not run
2. slight restructuring of the setup methods in both
  test classes
switch off printing in unittests