Remove unneeded version.h includes from include/

It was pointed out by 'make versioncheck' that some includes of
linux/version.h are not needed in include/.
This patch removes them.

When I last posted the patch, the ceph bit was ACK'ed by Sage Weil, so
I've added that below.

The pwc-ioctl change generated quite a bit of discussion about V4L version
numbers in general, but as far as I can tell, no concensus was reached on
what the long term solution should be, so in the mean time I think we
could start by just removing the unneeded include, which is why I'm
resending the patch with that hunk still included.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Acked-by: Sage Weil <sage@newdream.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>