online module: Don't fail when offline

If the system is offline, socket.gaierror is raised, the module crashes,
and shows `offline` indefinitely.

Catch that exception, and return False.

i3pystatus/core/util.py

@@ -373,7 +373,7 @@ class internet:
         try:
             socket.create_connection(cls.address, 1).close()
             return True
-        except OSError:
+        except (OSError, socket.gaierror):
             return False