[omemo] Fix missing imports

omemo/file_crypto.py

@@ -34,6 +34,7 @@ from io import BufferedWriter, FileIO, BytesIO
 from gi.repository import GLib
 from gajim.common import app
 from gajim.common import configpaths
+from gajim.plugins.plugins_i18n import _
 from gajim.gtk.dialogs import ErrorDialog, YesNoDialog
 from omemo.gtk.progress import ProgressWindow
 if os.name == 'nt':

omemo/omemo_connection.py

@@ -13,6 +13,8 @@ from gajim.common import helpers
 from gajim.common import configpaths
 from gajim.common.connection_handlers_events import MessageNotSentEvent
 
+from gajim.plugins.plugins_i18n import _
+
 from omemo.xmpp import (
     NS_NOTIFY, NS_OMEMO, NS_EME, NS_HINTS, BundleInformationAnnouncement,
     BundleInformationQuery, DeviceListAnnouncement, DevicelistQuery,

omemo/omemoplugin.py

@@ -34,6 +34,7 @@ from gajim import dialogs
 from gajim.common import app, ged
 from gajim.common.pep import SUPPORTED_PERSONAL_USER_EVENTS
 from gajim.plugins import GajimPlugin
+from gajim.plugins.plugins_i18n import _
 from gajim.groupchat_control import GroupchatControl
 
 from omemo.xmpp import DevicelistPEP