LU-2675 lnet: remove lnet/include/lnet/linux/

LU-2675 lnet: remove lnet/include/lnet/linux/

Remove the linux specific headers from lnet/include/lnet/linux/,
moving whatever was worthwhile from them to their parent headers or
elsewhere. Also remove lnet/klnds/socklnd/socklnd_lib-linux.h and
rename lnet/klnds/socklnd/socklnd_lib-linux.c to socklnd_lib.c.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: Id10683e95277791f9c99492907369a608b28a1fb
Reviewed-on: http://review.whamcloud.com/12932
Tested-by: Jenkins
Reviewed-by: Isaac Huang <he.huang@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: James Simmons <uja.ornl@gmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>