package/samba4: security bump to version 4.8.8

Fixes the following security issues:

- CVE-2018-14629 dns: Fix CNAME loop prevention using counter regression
- CVE-2018-16853: Fix S4U2Self crash with MIT KDC build
- CVE-2018-16853: Do not segfault if client is not set

For more info, see the release notes:
https://www.samba.org/samba/history/samba-4.8.8.html

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

package/samba4/samba4.hash

@@ -1,4 +1,4 @@
 # Locally calculated after checking pgp signature
-# https://download.samba.org/pub/samba/stable/samba-4.8.7.tar.asc
-sha256 0f6f67932e8bb23ab83b43070037ac452f9fc5f20763857d2b67e209ee7cd362  samba-4.8.7.tar.gz
+# https://download.samba.org/pub/samba/stable/samba-4.8.8.tar.asc
+sha256 3bc97ba7b827526b299e09a1c410f22d3a3c57bb46f1e67e8f93258945f8cf60  samba-4.8.8.tar.gz
 sha256 8ceb4b9ee5adedde47b31e975c1d90c73ad27b6b165a1dcd80c7c545eb65b903  COPYING

package/samba4/samba4.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-SAMBA4_VERSION = 4.8.7
+SAMBA4_VERSION = 4.8.8
 SAMBA4_SITE = https://download.samba.org/pub/samba/stable
 SAMBA4_SOURCE = samba-$(SAMBA4_VERSION).tar.gz
 SAMBA4_INSTALL_STAGING = YES