mariadb: fix build issue

The build breaks when Kerberos is available in staging dir. mariadb
build system exits with error:

CMake Error at libmariadb/cmake/plugins.cmake:43 (message):
  Invalid plugin type NO.  Allowed plugin types are DYNAMIC;STATIC;OFF

It doesn't like the definition "PLUGIN_AUTH_GSSAPI_CLIENT=NO" anymore.
We need to set it to "OFF" to make it happy.

Signed-off-by: Sebastian Kemper <sebastian_ml@gmx.net>

utils/mariadb/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=mariadb
 PKG_VERSION:=10.2.19
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL := \
@@ -383,7 +383,7 @@ CMAKE_OPTIONS += \
 	-DPLUGIN_TOKUDB=NO \
 	-DPLUGIN_AUTH_PAM=NO \
 	-DPLUGIN_AUTH_GSSAPI=NO \
-	-DPLUGIN_AUTH_GSSAPI_CLIENT=NO \
+	-DPLUGIN_AUTH_GSSAPI_CLIENT=OFF \
 	-DPLUGIN_CRACKLIB_PASSWORD_CHECK=NO
 
 # Help MariaDB find the correct libiconv.