Sinfo performance improvements

This avoids building hostlist information with NodeHostName and
NodeAddr information unless explisitly requested and can improve
performance for the default mode of operation by about 65%.
hostlist performance improvements

Reorder some logis in the hostlist functions for performance improvement
specifically for "if (A & B) ..." move the fastest tests first (test
A should take less time than test B).
Merge branch 'slurm-2.6'