LU-2675 libcfs: remove libcfs posix headers

LU-2675 libcfs: remove libcfs posix headers

Remove libcfs/include/libcfs/posix/. Include what was needed from
libcfs/posix/libcfs.h into libcfs/libcfs.h or in the appropriate .c
file.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: Ia3016c83f13554b617c5f4a6dcc86adf222d4e49
Reviewed-on: http://review.whamcloud.com/11987
Tested-by: Jenkins
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: James Simmons <uja.ornl@gmail.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>