clang-format: Fix bug in column layout.

Before (with 60 character limit in Google style):
  return {
      {aaaaaaaaaaaaaaaaaaaaaaaaa}, {aaaaaaaaaaaaaaaaa},
      {aaaaaaaaaaaaaaaaaaaaaaaaa}, {aaaaaaaaaaaaaaaaa}};
After:
  return {{aaaaaaaaaaaaaaaaaaaaaaaaa}, {aaaaaaaaaaaaaaaaa},
          {aaaaaaaaaaaaaaaaaaaaaaaaa}, {aaaaaaaaaaaaaaaaa}};

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@189327 91177308-0d34-0410-b5e6-96231b3b80d8