code changes for the following issue

1)resetting term->u.rtp.rfc2833 , if ADD/MODIFY SDP does not have rfc2833
2) calling DTMF removal from modify request also depends on rfc2833 present in sdp or not
3) calling EC disable from ADD/MODIFY api handler if sdp contains T38

src/mod/endpoints/mod_media_gateway/media_gateway_cmd_handler.c

@@ -743,7 +743,9 @@ switch_status_t handle_mg_add_cmd(megaco_profile_t* mg_profile, MgMgcoCommand *i
 
 	mg_apply_tdm_dtmf_removal(term, mg_ctxt);
 
-    mg_print_t38_attributes(term);
+	mg_apply_tdm_ec(term, mg_ctxt);
+	mg_print_t38_attributes(term);
+
 
     /********************************************************************/
 
@@ -1059,9 +1061,12 @@ switch_status_t handle_mg_modify_cmd(megaco_profile_t* mg_profile, MgMgcoCommand
 		}
 
 		mg_apply_tdm_dtmf_removal(term, mg_ctxt);
+
+		mg_apply_tdm_ec(term, mg_ctxt);
 		mg_print_t38_attributes(term);
 
 
+
 		/* SDP updated to termination */
 		if(SWITCH_STATUS_SUCCESS != megaco_activate_termination(term)) {
 			mg_profile->mg_stats->total_num_of_term_activation_failed_error++;

src/mod/endpoints/mod_media_gateway/media_gateway_stack.h

@@ -249,6 +249,7 @@ void mg_restart_inactivity_timer(megaco_profile_t* profile);
 
 switch_status_t mgco_process_mgc_failure(SuId suId);
 void mg_apply_tdm_dtmf_removal(mg_termination_t* term, mg_context_t *mg_ctxt);
+void mg_apply_tdm_ec(mg_termination_t* term, mg_context_t *mg_ctxt);
 
 
 /****************************************************************************************************************/