o reinitialize buffers on _log_init()

   attach

  log_set_argv0() to avoid reinitializing the log mutex.
  This avoids spurious debug messages on job stderr when default stderr
  logging is high (a rare but annoying bug)

 o Do not allow attach to tasks if tasks have exited

Added security_2_2.c

   (which currently has no contents)
 o build slurm-auth-none unconditionally

   to be sure"
 o src/slurmd/slurmd.c (_reconfigure) : reinitialize job credential key

reference if a reconfigure RPC was active at the same time.