fix leak of w->dir in new() when dir != nil

Reference: /n/atom/patch/applied2013/riodirleak
Date: Wed Dec  4 23:09:42 CET 2013
Signed-off-by: quanstro@quanstro.net

--- /sys/src/cmd/rio/rio.c	Wed Dec  4 23:09:07 2013
+++ /sys/src/cmd/rio/rio.c	Wed Dec  4 23:09:07 2013
@@ -1184,8 +1184,10 @@
 	}
 	wsetpid(w, pid, 1);
 	wsetname(w);
-	if(dir)
+	if(dir != nil){
+		free(w->dir);
 		w->dir = estrdup(dir);
+	}
 	chanfree(cpid);
 	return w;
 }
--- /sys/src/cmd/rio/util.c	Wed Dec  4 23:09:07 2013
+++ /sys/src/cmd/rio/util.c	Wed Dec  4 23:09:07 2013
@@ -82,6 +82,7 @@
 	if(p == nil)
 		error("strdup failed");
 	strcpy(p, s);
+	setmalloctag(p, getcallerpc(&s));
 	return p;
 }