[analyzer] 'Looping back to the head of the loop' diagnostics are prunable.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@152083 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/StaticAnalyzer/Core/BugReporter.cpp b/lib/StaticAnalyzer/Core/BugReporter.cpp
index 2b55433..73e00e4 100644
--- a/lib/StaticAnalyzer/Core/BugReporter.cpp
+++ b/lib/StaticAnalyzer/Core/BugReporter.cpp
@@ -1279,6 +1279,7 @@
           PathDiagnosticEventPiece *p =
             new PathDiagnosticEventPiece(L,
                                         "Looping back to the head of the loop");
+          p->setPrunable(true);
 
           EB.addEdge(p->getLocation(), true);
           PD.getActivePath().push_front(p);