[clang-tidy] Fixed header guards using clang-tidy llvm-header-guard check. NFC.

The patch was generated using this command:
$ clang-tidy/tool/run-clang-tidy.py -header-filter=.*clang-tidy.* -fix \
    -checks=-*,llvm-header-guard clang-tidy.*
$ svn revert --recursive clangt-tidy/llvm/
(to revert a few buggy fixes)

llvm-svn: 231669
diff --git a/clang-tools-extra/clang-tidy/google/UsingNamespaceDirectiveCheck.h b/clang-tools-extra/clang-tidy/google/UsingNamespaceDirectiveCheck.h
index 0c3b69a..1149697 100644
--- a/clang-tools-extra/clang-tidy/google/UsingNamespaceDirectiveCheck.h
+++ b/clang-tools-extra/clang-tidy/google/UsingNamespaceDirectiveCheck.h
@@ -7,8 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_GOOGLE_USING_NAMESPACE_CHECK_H
-#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_GOOGLE_USING_NAMESPACE_CHECK_H
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_GOOGLE_USINGNAMESPACEDIRECTIVECHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_GOOGLE_USINGNAMESPACEDIRECTIVECHECK_H
 
 #include "../ClangTidy.h"
 
@@ -34,4 +34,4 @@
 } // namespace tidy
 } // namespace clang
 
-#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_GOOGLE_USING_NAMESPACE_CHECK_H
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_GOOGLE_USINGNAMESPACEDIRECTIVECHECK_H