package:grub2: fix build error on linux missing libzfs

configure enables libzfs support on default.
This will break the build, on systems without libzfs.

Signed-off-by: Hans Ulli Kroll <ulli.kroll@googlemail.com>

SVN-Revision: 41935

package/boot/grub2/Makefile

@@ -48,12 +48,14 @@ CONFIGURE_ARGS += \
 	--disable-werror \
 	--disable-nls \
 	--disable-device-mapper \
+	--disable-libzfs \
 	--disable-grub-mkfont
 
 HOST_CONFIGURE_ARGS += \
 	--target=$(REAL_GNU_TARGET_NAME) \
 	--sbindir="$(STAGING_DIR_HOST)/bin" \
 	--disable-werror \
+	--disable-libzfs \
 	--disable-nls
 
 HOST_MAKE_FLAGS += \