Add prof.encryption_reset to Plugins API

issue #885

src/plugins/profapi.c

@@ -92,3 +92,5 @@ int (*prof_settings_string_list_clear)(char *group, char *key) = NULL;
 void (*prof_incoming_message)(char *barejid, char *resource, char *message) = NULL;
 
 void (*_prof_disco_add_feature)(const char *filename, char *feature) = NULL;
+
+void (*prof_encryption_reset)(const char *barejid) = NULL;