Merge pull request #549 from zenoss/feature/ZEN-14172

added mysql action for rebuild_zodb_session
remove jobs older than 24 hours
fixes ZEN-15143 set a no transform cache control so nginx doesn't garble the reponse
Merge pull request #551 from zenoss/feature/ZEN-15143

fixes ZEN-15143 set a no transform cache control so nginx doesn't garble...
handle job deletion edge cases
handle job deletion edge cases
Merge pull request #550 from zenoss/fix/ZEN-11014-2

remove jobs older than 24 hours
fixes ZEN-15161 reviewed by rterrel make the discovery step a little larger
attempt to trap poskey errors and recover