LU-6245 libcfs: move lucache from libcfs to lustre

LU-6245 libcfs: move lucache from libcfs to lustre

The lucache handling in libcfs is used only for
idmap handling in the obdclass and mdt layers.
Since this is the case we can move the lucache
handling into the lustre stack. As a bonus the
lucache will only be built when we enable server
support instead of the current state of it being
built for clients as well.

Signed-off-by: James Simmons <uja.ornl@gmail.com>
Change-Id: I812f2c5952ea79bd023435e5fac1955316c9c59f
Reviewed-on: http://review.whamcloud.com/13783
Tested-by: Jenkins
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>