[analyzer] Add a clone() method to BugReporterVisitor, so that we'll be able to reset diagnostic generation.

llvm-svn: 153368
diff --git a/clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp
index 502fb1e..8f4502c 100644
--- a/clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp
@@ -197,7 +197,7 @@
   /// The bug visitor which allows us to print extra diagnostics along the
   /// BugReport path. For example, showing the allocation site of the leaked
   /// region.
-  class MallocBugVisitor : public BugReporterVisitor {
+  class MallocBugVisitor : public BugReporterVisitorImpl<MallocBugVisitor> {
   protected:
     enum NotificationMode {
       Normal,