CEL: Expose parking retreiver in extra field

This exposes the retreiver of a parked call under the "retreiver" key
of the extra field when this information is available.

Review: https://reviewboard.asterisk.org/r/3608/
........

Merged revisions 416148 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@416149 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/cel.c

@@ -1241,7 +1241,14 @@ static void cel_parking_cb(
 		break;
 	}
 
-	extra = ast_json_pack("{s: s}", "reason", reason);
+	if (parked_payload->retriever) {
+		extra = ast_json_pack("{s: s, s: s}",
+			"reason", reason,
+			"retriever", parked_payload->retriever->name);
+	} else {
+		extra = ast_json_pack("{s: s}", "reason", reason);
+	}
+
 	if (extra) {
 		cel_report_event(parked_payload->parkee, AST_CEL_PARK_END, NULL, extra, NULL);
 	}