call_control: avoid internal flags conflicts with mediaproxy

- use internal flag 28 for marking requests handled by call_control, the
  old value, 30, being used by mediaproxy module, resulting in engaging
  media relay
- reported and solution by Reda Aouad

modules_k/call_control/call_control.c

@@ -49,7 +49,7 @@
 
 MODULE_VERSION
 
-#define FL_USE_CALL_CONTROL       (1<<30) // use call control for a dialog
+#define FL_USE_CALL_CONTROL       (1<<28) // use call control for a dialog
 
 #if defined(__GNUC__) && !defined(__STRICT_ANSI__)
 # define INLINE inline

parser/msg_parser.h

@@ -120,6 +120,9 @@ enum request_method {
 #define FL_ADD_LOCAL_RPORT  (1 << 11) /*!< add 'rport' to local via hdr */
 #define FL_SDP_BODY     (1 << 12)  /*!< msg has SDP in body */
 
+/* WARNING: Value (1 << 28) is temporarily reserved for use in kamailio call_control
+ * module (flag  FL_USE_CALL_CONTROL )! */
+
 /* WARNING: Value (1 << 29) is temporarily reserved for use in kamailio acc
  * module (flag FL_REQ_UPSTREAM)! */