Revert "Apply modernize-use-default to clang-tools-extra."

Breaks the build in GCC 4.7.2 (see
http://lab.llvm.org:8011/builders/perf-x86_64-penryn-O3 for example)

This reverts commit r250824.

llvm-svn: 250862
diff --git a/clang-tools-extra/modularize/CoverageChecker.cpp b/clang-tools-extra/modularize/CoverageChecker.cpp
index a0a979e..b3c4227 100644
--- a/clang-tools-extra/modularize/CoverageChecker.cpp
+++ b/clang-tools-extra/modularize/CoverageChecker.cpp
@@ -83,7 +83,7 @@
 class CoverageCheckerCallbacks : public PPCallbacks {
 public:
   CoverageCheckerCallbacks(CoverageChecker &Checker) : Checker(Checker) {}
-  ~CoverageCheckerCallbacks() override = default;
+  ~CoverageCheckerCallbacks() override {}
 
   // Include directive callback.
   void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,