Add connection_get_profanity_identifier stub

And move defintion to xmpp.h

src/xmpp/connection.h

@@ -64,6 +64,4 @@ void connection_remove_available_resource(const char *const resource);
 
 char* connection_create_stanza_id(void);
 
-char *connection_get_profanity_identifier(void);
-
 #endif

src/xmpp/xmpp.h

@@ -140,6 +140,8 @@ GList* connection_get_available_resources(void);
 gboolean connection_supports(const char *const feature);
 char* connection_jid_for_feature(const char *const feature);
 
+char *connection_get_profanity_identifier(void);
+
 char* message_send_chat(const char *const barejid, const char *const msg, const char *const oob_url,
     gboolean request_receipt);
 char* message_send_chat_otr(const char *const barejid, const char *const msg, gboolean request_receipt);