Improve error message when GPG is now found during initialization. Issues #168 and #98

mayan/apps/django_gpg/api.py

@@ -127,9 +127,12 @@ class GPG(object):
 
         try:
             self.gpg = gnupg.GPG(**kwargs)
+        except OSError as exception:
+            raise GPGException('ERROR: GPG initialization error; Make sure the GPG binary is properly installed; %s' % exception)
         except Exception as exception:
             raise GPGException('ERROR: GPG initialization error; %s' % exception)
 
+
     def verify_file(self, file_input, detached_signature=None, fetch_key=False):
         """
         Verify the signature of a file.