Cleanup: __kmp_env_* variables

Removed unused __kmp_env_* variables. Also clangified other people's code.

Patch by Terry Wilmarth

Differential Revision: https://reviews.llvm.org/D35808


git-svn-id: https://llvm.org/svn/llvm-project/openmp/trunk@309000 91177308-0d34-0410-b5e6-96231b3b80d8