gnutls: security bump to version 3.2.15

Fixes GNUTLS-SA-2014-3 (CVE-2014-3466).

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/gnutls/gnutls.mk

@@ -5,7 +5,7 @@
 ################################################################################
 
 GNUTLS_VERSION_MAJOR = 3.2
-GNUTLS_VERSION = $(GNUTLS_VERSION_MAJOR).14
+GNUTLS_VERSION = $(GNUTLS_VERSION_MAJOR).15
 GNUTLS_SOURCE = gnutls-$(GNUTLS_VERSION).tar.xz
 GNUTLS_SITE = ftp://ftp.gnutls.org/gcrypt/gnutls/v$(GNUTLS_VERSION_MAJOR)
 GNUTLS_LICENSE = GPLv3+ LGPLv2.1+