don't leak the name of the subfont

Reference: /n/atom/patch/applied2013/freesubfleak
Date: Wed Dec  4 23:08:01 CET 2013
Signed-off-by: quanstro@quanstro.net

--- /sys/src/libdraw/freesubfont.c	Wed Dec  4 23:07:53 2013
+++ /sys/src/libdraw/freesubfont.c	Wed Dec  4 23:07:53 2013
@@ -11,6 +11,7 @@
 	if(f->ref > 0)
 		return;
 	uninstallsubfont(f);
+	free(f->name);
 	free(f->info);	/* note: f->info must have been malloc'ed! */
 	freeimage(f->bits);
 	free(f);