Attempt to mitigate possible cause for Bug#3823 by replacing use of F_SETLKW
when updating scoreboard entries to F_SETLK, and handling interruptions.
This should reduce any (potentially long) blocking behaviors.
Merge pull request #12 from proftpd/scoreboard-entry-locking-bug3823

Attempt to mitigate possible cause for Bug#3823 by replacing use of F_SE...