Revert "LU-2327 ptlrpc: ptlrpc_check_set() to warn"

This reverts commit 3744d3c28ab99ec02f5a06b0aa123875c3acd093.
LU-2327 ptlrpc: ptlrpc_check_set warn of long wait on spin_lock()

Make ptlrpc_check_set() warn if aquiring the spin_lock() takes
more than 5 seconds (and then every 3600 seconds after that).

Prints CERROR message and backtrace.

Signed-off-by: Christopher J. Morrone <morrone2@llnl.gov>
Change-Id: Ia2dce849c22af19ec62ef6fdc46d6786e8a1497c