siptrace: update doc with editor

(cherry picked from commit d00f198d74a3c152c2b66cb9569d876aad610d95)

src/modules/siptrace/doc/siptrace.xml

@@ -28,6 +28,11 @@
 		<surname>Mierla</surname>
 		    <email>[email protected]</email>
 	    </editor>
+	<editor>
+		<firstname>Giacomo</firstname>
+		<surname>Vacca</surname>
+		<email>[email protected]</email>
+	</editor>
 	</authorgroup>
 	<copyright>
 	    <year>2010</year>