Fix usleep(3) return type to be POSIX-compliant.

POSIX usleep(3) returns 0 on successful completion, -1 otherwise:
  http://www.opengroup.org/onlinepubs/007908799/xsh/usleep.html

This was found by an external user porting native code:
  http://groups.google.com/group/android-porting/browse_thread/thread/674848f001db0292
2 files changed