Call destroy from ~BasicCallGraph.

This fix a memory leak found by valgrind.

Calling it from the base class destructor would not destroy the BasicCallGraph
bits.

FIXME: BasicCallGraph is the only thing that inherits from CallGraph. Can
we merge the two?

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193412 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Analysis/IPA/CallGraph.cpp

@@ -46,12 +46,16 @@ public:
     ExternalCallingNode(0), CallsExternalNode(0) {
       initializeBasicCallGraphPass(*PassRegistry::getPassRegistry());
     }
+  ~BasicCallGraph() {
+    destroy();
+  }
 
   // runOnModule - Compute the call graph for the specified module.
   virtual bool runOnModule(Module &M) {
     CallGraph::initialize(M);
     
     ExternalCallingNode = getOrInsertFunction(0);
+    assert(!CallsExternalNode);
     CallsExternalNode = new CallGraphNode(0);
     Root = 0;