fix leak.

Reference: /n/sources/patch/applied/subfont-leak
Date: Sun Jul 23 19:47:41 CES 2006
Signed-off-by: quanstro@quanstro.net

--- /sys/src/libdraw/subfontname.c	Sun Jul 23 19:43:37 2006
+++ /sys/src/libdraw/subfontname.c	Mon Jul 24 03:15:32 2006
@@ -40,11 +40,13 @@
 			free(t);
 			return tmp2;
 		}
+		free(tmp2);
 	}
 
 	/* try default */
 	if(access(t, AREAD) == 0)
 		return t;
 
+	free(t);
 	return nil;
 }