BSD - Fix issue reported by robfig

BSD - Fix issue reported by robfig

EINTR can be returned by kevent in two cases:
1) fork() while parent/child is calling kevent() will result in the
process calling kevent() to get EINTR while other process is registering
the same kqueue at the kernel level.
2) A file event occurs before timeout expires, but is not yet on the
queue to be returned by kevent().

In either case, we can ignore the error and continue as if timeout
expired without any events.