Fix a clang warning
Fix a clang warning

Change-Id: I5ef32c6329f1f75efb30b16519b8de146a8339fa

ikoruk/ceres-solver,ysonggit/ceres-solver,timfel/ceres-bin,ikoruk/ceres-solver,entylop/ceres-solver,jmwalls/ceres-solver-fork,ysonggit/ceres-solver,timfel/ceres-bin,ikoruk/ceres-solver,stonier/ceres_solver,ikoruk/ceres-solver,DougFirErickson/ceres-solver,kartikkumar/ceres-solver,entylop/ceres-solver,kartikkumar/ceres-solver,kartikkumar/ceres-solver,entylop/ceres-solver,DougFirErickson/ceres-solver,timfel/ceres-bin,DougFirErickson/ceres-solver,stonier/ceres_solver,ikoruk/ceres-solver,timfel/ceres-bin,stonier/ceres_solver,whuaegeanse/ceres-solver,entylop/ceres-solver,jmwalls/ceres-solver-fork,DougFirErickson/ceres-solver,whuaegeanse/ceres-solver,ysonggit/ceres-solver,whuaegeanse/ceres-solver,jmwalls/ceres-solver-fork,stonier/ceres_solver,ysonggit/ceres-solver,jmwalls/ceres-solver-fork,kartikkumar/ceres-solver,whuaegeanse/ceres-solver