[openpgp] Fix _() import

Fixes #358

openpgp/gtk/key.py

@@ -25,6 +25,7 @@ from gajim.common import app
 from gajim.common.const import DialogButton, ButtonAction
 
 from gajim.gtk import NewConfirmationDialog
+from gajim.plugins.plugins_i18n import _
 
 from openpgp.modules.util import Trust
 

openpgp/gtk/wizard.py

@@ -24,6 +24,7 @@ from gi.repository import Gtk
 from gi.repository import GLib
 
 from gajim.common import app
+from gajim.plugins.plugins_i18n import _
 
 log = logging.getLogger('gajim.plugin_system.openpgp.wizard')
 

openpgp/pgpplugin.py

@@ -30,6 +30,7 @@ from gajim.common import configpaths
 from gajim.common import helpers
 from gajim.common.const import CSSPriority
 from gajim.gtk.dialogs import ErrorDialog
+from gajim.plugins.plugins_i18n import _
 
 from openpgp.modules.util import NS_NOTIFY
 from openpgp.modules.util import ENCRYPTION_NAME