Clean up the epan_dissect_t in the normal code path.

We initialized it, but only cleaned it up in an error code path, not in
the regular code path.  That could leak memory.

Change-Id: Ic6689163ca58990fa5091b23e7ab2e0292eed76c
Reviewed-on: https://code.wireshark.org/review/29930
Reviewed-by: Guy Harris <guy@alum.mit.edu>

ui/qt/rtp_analysis_dialog.cpp

@@ -1599,6 +1599,8 @@ void RtpAnalysisDialog::findStreams()
     }
     fwd_statinfo_.id.ssrc = fvalue_get_uinteger(&((field_info *)gp->pdata[0])->value);
 
+    epan_dissect_cleanup(&edt);
+
     /* Register the tap listener */
     memset(&tapinfo_, 0, sizeof(rtpstream_tapinfo_t));
     tapinfo_.tap_data = this;