clang-format: Fix ObjC literal indentation in Google style.

Style guide demands a two-space indent.

Before:
  NSArray *arguments = @[
      kind == kUserTicket ? @"--user-store" : @"--system-store",
      @"--print-tickets",
      @"--productid",
      @"com.google.Chrome"
  ];

After:
  NSArray *arguments = @[
    kind == kUserTicket ? @"--user-store" : @"--system-store",
    @"--print-tickets",
    @"--productid",
    @"com.google.Chrome"
  ];

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193168 91177308-0d34-0410-b5e6-96231b3b80d8