Update .arcconfig to point to reviews.llvm.org

Mostly a test review and commit.

Reviewers: tfiala

Differential Revision: http://reviews.llvm.org/D3834

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@209237 91177308-0d34-0410-b5e6-96231b3b80d8