Fixes small memory leak introduced in commit 5669a22081
Reported-by: Julien Cristau <jcristau@debian.org>
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>

Hint: Upstream commit 5669a22081 is "integer overflow in _XF86BigfontQueryFont() [CVE-2013-1981 2/13]"
Backported-to-NX-by: Ulrich Sibiller <uli42@gmx.de>