Fix unit tests for ModuleLoader change in r168961.

llvm-svn: 168962
diff --git a/clang/unittests/Lex/PPCallbacksTest.cpp b/clang/unittests/Lex/PPCallbacksTest.cpp
index b388527..02b374b 100644
--- a/clang/unittests/Lex/PPCallbacksTest.cpp
+++ b/clang/unittests/Lex/PPCallbacksTest.cpp
@@ -32,10 +32,11 @@
 
 // Stub out module loading.
 class VoidModuleLoader : public ModuleLoader {
-  virtual Module *loadModule(SourceLocation ImportLoc, ModuleIdPath Path,
-    Module::NameVisibilityKind Visibility,
-    bool IsInclusionDirective) {
-      return 0;
+  virtual ModuleLoadResult loadModule(SourceLocation ImportLoc, 
+                                      ModuleIdPath Path,
+                                      Module::NameVisibilityKind Visibility,
+                                      bool IsInclusionDirective) {
+    return ModuleLoadResult();
   }
 };