Remove unneeded version.h includes from drivers/block/

It was pointed out by 'make versioncheck' that some includes of
linux/version.h are not needed in drivers/block/.
This patch removes them.
Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/block/drbd/drbd_int.h

@@ -28,7 +28,6 @@
 
 #include <linux/compiler.h>
 #include <linux/types.h>
-#include <linux/version.h>
 #include <linux/list.h>
 #include <linux/sched.h>
 #include <linux/bitops.h>

drivers/block/xen-blkback/common.h

@@ -27,7 +27,6 @@
 #ifndef __XEN_BLKIF__BACKEND__COMMON_H__
 #define __XEN_BLKIF__BACKEND__COMMON_H__
 
-#include <linux/version.h>
 #include <linux/module.h>
 #include <linux/interrupt.h>
 #include <linux/slab.h>