changed daemon shutdown expression to work with partitionable slots
Modify condor shutdown extression to work also with dynamic slots (ticket v3/5359)

The new expression uses attributes defined in condor 8.2. If these are not available the expression
falls back to the previous one (BC82 in the expression).
With the new attributes (TotalJobs) are defined the behavior (AC82) is close to the one specified
in the documentation:
- if no job is assigned the shutdown is triggered after GLIDEIN_Max_Idle
- if jobs are assigned and the glidein goes back to idle (ExpectedMachineGracefulDrainingCompletion),
the shutdown is triggered after GLIDEIN_Max_Tail
The expression should work also with old classads but I had no condor pre 7.5 to test it
parenthesis added to isolate more an expression; new daemon shutdown expression used aldo in condor_config.check.include
improve names and comments of daemon shutdown expression
improve names of daemon shutdown expression (part 2 _JOB -> _TAIL)
Removed second schedd form default user submit condfiguration [#3775]

Commented out the section form the condor config file and add note to make
it easy for a user to add it back if desired
Documentation still covers it. Added a clarification that it refers to user
schedd and not glideins schedd.
added extra conditions in daemon shutdown expression checking for undefined attributes
Merge remote-tracking branch 'origin/v3/5359' into branch_v3_2
Merge branch 'v3/3775' into branch_v3_2