removed old send/recv buffer calls, they weren't being used and aren't compatible with the new auth credential transport changes

If you revoke a credential that has not been used a credential_state object needs to be created

associated with it.

on all updates. reduce frequency of periodic state saves to once every
300 seconds.

state save files (i.e. if I/O did not complete).

   vector

set io_thread to call pthread_exit
I don't think this is a problem

adde fcntl to slurm_protocol for non-blocking io

specified time interval to pass (avoid saving initial configuration
to state save files).