backfill - minor code re-order

This reording of some code results in cleaner logic
Correct PTY use FAQ
Fix shared=yes support

Correct support for partition with Shared=YES configuration.
Previous logic would share resources for jobs by default
(i.e. if user did not explicitly request --exclusive).
bug 758
Honor job exclusive with reserved cores

If job requests --exclusive then do not use nodes which have any cores in an
advanced reservation. Previously the job would be allocated all of the cores
outside of the advanced reservation.
select/cons_res log change

Disable some logging that would be very slow unless
the _DEBUG flag is set in the plugin
Fix job --exclusive option enforcement

If job requests --exclusive then do not use nodes which have any cores in an
advanced reservation. Also prevents case where nodes can be shared by other
jobs.
Merge branch 'slurm-14.03'