* flock.cc (class inode_t): Add i_wait member and matching methods
wait(), unwait(), and waiting().
(inode_t::inode_t): Initialize i_wait to 0.
(fhandler_disk_file::lock): Only remove node if no other thread is
waiting for a blocking lock.
(lf_setlock): Manipulate node->i_wait to signal that a thread is
waiting for a blocking lock in this node.
(lf_findoverlap): Reinstantiate SELF test as in original code.