samba4: security bump to version 4.5.16

CVE-2018-1050: Vulnerability to a denial of service attack when the RPC
spoolss service is configured to be run as an external daemon.

https://www.samba.org/samba/security/CVE-2018-1050.html

CVE-2018-1057: Authenticated users might change any other users'
passwords, including administrative users and privileged service
accounts (eg Domain Controllers).

https://www.samba.org/samba/security/CVE-2018-1057.html

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/samba4/samba4.hash

@@ -1,2 +1,2 @@
 # Locally calculated
-sha256  811bf727892a1e1e3d170eb72eb39c43d06ed8ff557e5e036a41aabc19008e94 samba-4.5.15.tar.gz
+sha256  3a3356faab1694680e2ccd7fdf051ab1bbd3b0d058fc1f671e135dd2d1eae1aa samba-4.5.16.tar.gz

package/samba4/samba4.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-SAMBA4_VERSION = 4.5.15
+SAMBA4_VERSION = 4.5.16
 SAMBA4_SITE = https://download.samba.org/pub/samba/stable
 SAMBA4_SOURCE = samba-$(SAMBA4_VERSION).tar.gz
 SAMBA4_INSTALL_STAGING = YES