Remove _too_many_fragments() function since DPCS is now smart enough to

avoid highly fragmented resource allocations.
Add list of excluded nodes to job info dumpped and reported.
Fix how mis-matched RPC version number are handled. Let error code get
back to the API function.
Dump job state information upon each job's termination via plugin.
Re-issue incomplete write requests in job/partition state save.
Make slurmctld continue proper operation without any default partition
(gnats:317).
Add command/RPC to delete a partition.
Retry socket connection for slurmd/io.c as needed (gnats:253).