clang-format: Add a space in ObjC protocols.

Before:
  @interface Foo (HackStuff)<MyProtocol>

After:
  @interface Foo (HackStuff) <MyProtocol>

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@214508 91177308-0d34-0410-b5e6-96231b3b80d8