Fix a bunch of [-Werror,-Winconsistent-missing-override] errors.


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@221231 91177308-0d34-0410-b5e6-96231b3b80d8
Fix one more [-Werror,-Winconsistent-missing-override] error.


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@221232 91177308-0d34-0410-b5e6-96231b3b80d8