Add print method to not get silly warning from analyze

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@6981 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Analysis/DataStructure/GraphChecker.cpp

@@ -52,6 +52,7 @@ namespace {
       }
       AU.setPreservesAll();
     }
+    void print(std::ostream &O, const Module *M) const {}
 
   private:
     void verify(const DSGraph &G);