stop leak

Reference: /n/sources/patch/applied/plumbleak
Date: Tue Jul  1 23:21:43 CES 2008
Signed-off-by: quanstro@quanstro.net

--- /sys/src/libplumb/mesg.c	Tue Jul  1 23:21:39 2008
+++ /sys/src/libplumb/mesg.c	Tue Jul  1 23:21:38 2008
@@ -26,6 +26,7 @@
 		if(s == nil)
 			return -1;
 		f = open(s, ORDWR);
+		free(s);
 		if(f < 0)
 			return -1;
 		if(mount(f, -1, "/mnt/plumb", MREPL, "") < 0){