Fixed gcc build warnings

+ vim 'fixed' line endings in json_value.cpp

Contributed-by:  Johannes Doerfert <doerfert@cs.uni-saarland.de>

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@206044 91177308-0d34-0410-b5e6-96231b3b80d8