Update froniter client to 2.8.11.

Fixes #962.
Supersedes #994.
Merge pull request #1020 from degano/frontier_2811_73X

Update froniter client to 2.8.11.
Merge remote branch 'origin/IB/CMSSW_7_2_X/stable' into IB/CMSSW_7_0_X/stable
Add CMSSW_7_3_X_THREADED IB for slc6_amd64_gcc481
remove CMSSW_7_3_X_THREADED IB for slc6_amd64_gcc481
Add CMSSW_7_3_ROOT6_X IB for slc6_amd64_gcc481
Merge remote branch 'origin/IB/CMSSW_7_0_X/stable' into IB/CMSSW_7_0_X/stable
Merge remote branch 'origin/IB/CMSSW_7_1_X/stable' into IB/CMSSW_7_0_X/stable
Merge remote branch 'origin/IB/CMSSW_7_2_X/stable' into IB/CMSSW_7_0_X/stable
Merge remote branch 'origin/IB/CMSSW_7_3_X/stable' into IB/CMSSW_7_0_X/stable