LU-9859 libcfs: initialize bit_wait_table

LU-9859 libcfs: initialize bit_wait_table

With older platforms wait_event_var() is missing so we needed to
provide are own version. This included creating a local
bit_wait_table like the kernel has. That table was never properly
initialized so it can cause failures under the right conditions.

Test-Parameters: trivial

Fixes: 372ef85512 ("LU-11089 obd: use wait_event_var() in lu_context_key_degister()")
Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Change-Id: I310d37da7c1b54166224b367446cc905c02ab8bc
Reviewed-on: https://review.whamcloud.com/35567
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Neil Brown <neilb@suse.com>
Reviewed-by: Shaun Tancheff <stancheff@cray.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>