[httpupload] Make sure httpupload is last

The oob tag is only added when a body tag exists with the same content. (means not unencrypted)
If any encryption plugin is active, there should be no cleartext body.
So no oob tag is added to encrypted messages.

This patch exists only for the OTR plugin.

httpupload/httpupload.py

@@ -88,7 +88,7 @@ class HttpuploadPlugin(GajimPlugin):
             'agent-info-received': (
                 ged.PRECORE, self.handle_agent_info_received),
             'stanza-message-outgoing': (
-                ged.PRECORE, self.handle_outgoing_stanza),
+                99, self.handle_outgoing_stanza),
             'raw-iq-received': (
                 ged.PRECORE, self.handle_iq_received)}
         self.gui_extension_points = {