Nautilus Extension: fix gettext usage

Apparently the way we did this in GSConnect never actually worked, it
just took years for someone to report it. Since this extension is
derived from GSConnect's it's likely that's the case here, too.

This is the appropriate way to use gettext according to the Python3
documentation.

nautilus-extension/kdeconnect-share.py

@@ -29,12 +29,17 @@ __app_disp_name__ = "Share files to your phone via KDE Connect"
 __website__ = "https://community.kde.org/KDEConnect"
 
 import gettext
-import locale
 from functools import partial
 
 from gi.repository import Nautilus, Gio, GLib, GObject
 
-_ = gettext.gettext
+try:
+    i18n = gettext.translation('kdeconnect-nautilus-extension')
+    _ = i18n.gettext
+except (IOError, OSError) as e:
+    print('kdeconnect-nautilus: {0}'.format(e.strerr))
+    i18n = gettext.translation('kdeconnect-nautilus-extension', fallback=True)
+    _ = i18n.gettext
 
 class KdeConnectShareExtension(GObject.GObject, Nautilus.MenuProvider):
     """A context menu for sending files via KDE Connect."""
@@ -55,12 +60,6 @@ class KdeConnectShareExtension(GObject.GObject, Nautilus.MenuProvider):
 
         self.devices = {}
 
-        try:
-            locale.setlocale(locale.LC_ALL, '')
-            gettext.bindtextdomain('kdeconnect-nautilus-extension')
-        except Exception as e:
-            print(e)
-
         self.dbus = Gio.DBusProxy.new_for_bus_sync(
             Gio.BusType.SESSION,
             Gio.DBusProxyFlags.NONE,