LU-14289 ptlrpc: rename cfs_binheap to simply binheap

LU-14289 ptlrpc: rename cfs_binheap to simply binheap

As the binheap code is no longer part of libcfs, the cfs_ prefix is
misleading.  As this code is local to one module and doesn't conflict
with anything global, there is no need for a prefix at all.  So change
cfs_binheap to binheap.

This patch was prepare using 'sed', then fixing a few text-alignment
issues caused by the loss of those 4 characters.

Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: I168bec50898ec7b9ab72dc91b080af4852ddb3a4
Reviewed-on: https://review.whamcloud.com/41375
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>