LU-8837 lustre: make uapi...lustre_disk.h unnecessary on client

LU-8837 lustre: make uapi...lustre_disk.h unnecessary on client

uapi/linux/lustre/lustre_disk.h doesn't contain anything that is
needed for client-only code, but that code doesn't compile with the
file excluded, largely due to dependency on IS_SERVER() and related
macros.

So for client-only code provide stubs for IS_SERVER() and related
macros, and don't include the uapi...lustre_disk.h file.

This will cause some code to now be compiled-out on client-only, and
allows some #ifdefs to be removed.

A few function need to be protected with #ifdef HAVE_SERVER_SUPPORT,
and llog_server.o needs to be disabled for client-only compiles.

Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: I19c5b1612108e448f8b6a1fe3d3a448aa4abdd2a
Reviewed-on: https://review.whamcloud.com/41994
Reviewed-by: James Simmons <jsimmons@infradead.org>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>