Make PGP encoding configurable

python-gnupg uses latin1 as default encoding because GPG itself uses
latin1 as default.
We should not override this default with getpreferredencoding, because
getpreferredencoding maybe returns something else than what GPG is configured
on that system.

Example: On Windows
GPG is run in default mode with 'latin1'
getpreferredencoding returns 'cp1252'

The approach would be now to default to latin1 as it is GPGs default.
And if the User sets a different ecoding for GPG he has to set it in
Gajim aswell.

src/common/config.py

@@ -315,6 +315,7 @@ class Config:
             'positive_184_ack': [ opt_bool, False, _('If enabled, Gajim will show an icon to show that sent message has been received by your contact')],
             'show_avatar_in_tabs': [ opt_bool, False, _('Show a mini avatar in chat window tabs and in window icon')],
             'use_keyring': [opt_bool, True, _('If True, Gajim will use the Systems Keyring to store account passwords.')],
+            'pgp_encoding': [ opt_str, '', _('Sets the encoding used by python-gnupg'), True],
     }, {})
 
     __options_per_key = {

src/common/gpg.py

@@ -22,9 +22,10 @@
 ## along with Gajim. If not, see <http://www.gnu.org/licenses/>.
 ##
 
-from common.gajim import HAVE_GPG, GPG_BINARY
 import os
 import logging
+from common import gajim
+from common.gajim import HAVE_GPG, GPG_BINARY
 
 if HAVE_GPG:
     import gnupg
@@ -33,7 +34,9 @@ if HAVE_GPG:
     class GnuPG(gnupg.GPG):
         def __init__(self, use_agent=False):
             gnupg.GPG.__init__(self, gpgbinary=GPG_BINARY)
-            self.encoding = 'utf-8'
+            encoding = gajim.config.get('pgp_encoding')
+            if encoding:
+                self.encoding = encoding
             self.decode_errors = 'replace'
             self.passphrase = None
             self.use_agent = use_agent