clang-format: Indent correctly in conditional expressions after return.

This only applies when not aligning after the return itself (which is
commonly done for C++.

Before:
  return aaaaaaaaaa
      ? bbbbbbbbbb(
             bbbbbb)  // This is indented relative to aaaaaaaaaa.
      : b;

After:
  return aaaaaaaaaa
      ? bbbbbbbbbb(
            bbbbbb)
      : b;

llvm-svn: 223694