Plug memory leak in duration()

Strdup should be followed by a free()...

Signed-off-by: Anton Lundin <glance@acc.umu.se>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

parse-xml.c

@@ -550,6 +550,7 @@ static void duration(char *buffer, void *_time)
 		char *dot = strchr(mybuffer,'.');
 		*dot = ':';
 		sampletime(mybuffer, _time);
+		free(mybuffer);
 	} else {
 		sampletime(buffer, _time);
 	}