CMSSW_7_5_7

Changes since CMSSW_7_5_6_patch1:

Merge due to automatic forward port compare to previous

CMSDIST Changes between Tags REL/CMSSW_7_5_6_patch1/slc6_amd64_gcc491 and REL/CMSSW_7_5_7/slc6_amd64_gcc491:

compare to previous

1. 1978 from @cms-sw: Revert “Upgrade Frontier client to version 2.8.14 and pacparser to 1.3.5.” created: 2015-11-22 08:56:59 merged: 2015-11-22 08:57:07