Update the django_gpg app to work with the latest version of the
python-gnupg package (0.4.3).
The python-gnupg now returns a more clear error message to
differentiate between a bad passphrase and a missing passphrase.
This improments allows the django_gpg to simplify its error
message parsing and remove the literals:
"ERROR_MSG_NEED_PASSPHRASE" and "ERROR_MSG_GOOD_PASSPHRASE".
Signed-off-by: Roberto Rosario <Roberto.Rosario@mayan-edms.com>