Decrease pthread create retry sleep

If pthread_create call fails, decrease sleep before retry from
1 sec to 0.1 sec
Do msg retry logic at 0.1 sec intervals

rather than 1 sec interval retries
Move state save after scheduling new batch job

This is related to defering batch job scheduling if there
are a bunch of requests pending
Minor code refactoring for performance
added SchedulerParameters option of max_rpc_cnt

Disables job scheduling when there are too many pending RPCs
Handle invalid SchedulerParameters better

Rather than treat invalid SchedulerParameters options as a fatal
error, print an error and use to the default value.
Merge branch 'slurm-2.6' into slurm-14.03

Conflicts:
	src/common/slurm_protocol_api.c
	src/slurmctld/job_scheduler.c
	src/slurmctld/proc_req.c