package/samba4: security bump to version 4.5.12

Fixes CVE-2017-11103:

All versions of Samba from 4.0.0 onwards using embedded Heimdal
Kerberos are vulnerable to a man-in-the-middle attack impersonating
a trusted server, who may gain elevated access to the domain by
returning malicious replication or authorization data.

Samba binaries built against MIT Kerberos are not vulnerable.

https://www.samba.org/samba/history/samba-4.5.12.html

[Peter: add CVE info]
Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/samba4/samba4.hash

@@ -1,2 +1,2 @@
 # Locally calculated
-sha256 7cb753f5f6d5527ef40d4c1f47dacafb7c876cb304b4906ccb390c6a18477714  samba-4.5.10.tar.gz
+sha256 f4c17123e3cc852a5ecc7e38884b00deab57632b9519aebc243e2a94b9b5ace4  samba-4.5.12.tar.gz

package/samba4/samba4.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-SAMBA4_VERSION = 4.5.10
+SAMBA4_VERSION = 4.5.12
 SAMBA4_SITE = https://download.samba.org/pub/samba/stable
 SAMBA4_SOURCE = samba-$(SAMBA4_VERSION).tar.gz
 SAMBA4_INSTALL_STAGING = YES