No AVworkers when PM_RECOVERY_CONSISTENT

When pmState == PM_RECOVERY_CONSISTENT we run
SignalAutovacWorkers(SIGTERM);
at normal shutdown

This currently does nothing, but since there aren't ever going to be any
AVworkers at this time we should be explicitly skipping this. That
should avoid misunderstanding the code and avoid any future side
effects.

Low priority, minor.

Removed while updating earlier work on HS.

--
 Simon Riggs           www.2ndQuadrant.com