staging: lustre: set task state before scheduling in lnet_sock_accept

In the original code change when libcfs_sock_accept() was made
into lnet_sock_accept() a call to set_current_state(TASK_INTERRUPTIBLE)
got dropped which was restored. For upstream this is an
optimization of calling init_waitqueue_entry() only if
accept() return -EAGAIN. Also we can remove setting the
task to TASK_RUNNING that is not needed.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-6407
Reviewed-on: http://review.whamcloud.com/14265


Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Amir Shehata <amir.shehata@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>