clang-format: Fix regression in formatting of braced initializers.

Before:
  Node n{1, Node{1000}, //
                2};

After:
  Node n{1, Node{1000}, //
         2};

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@216540 91177308-0d34-0410-b5e6-96231b3b80d8