Fixes for the following unit tests: - shouldSignMessage: key ring cache isn't invalidated when importing revocation certificates. - testGetGpgFeatureForWhenVersionIsSupported: minimal supported version was too old. - Tests for files.jsm: undefined symbol EnigmailLog. - returns*WhenConfiguredToUseTor: mocked subprocess.call() interface has changed. - pEp shouldEncryptMessage: Typo & changed interface.