Remove useless return-value from RetransformClassesDirect

This call simply executes a bunch of callbacks. It cannot fail. We do
not need to return and check a jvmtiError return value.

Test: ./test.py --host
Change-Id: I164e4979526ec18b258ad300f959b20a9fb417f2
diff --git a/openjdkjvmti/transform.h b/openjdkjvmti/transform.h
index 16e8bd6..40c7267 100644
--- a/openjdkjvmti/transform.h
+++ b/openjdkjvmti/transform.h
@@ -56,7 +56,7 @@
       art::Thread* self,
       /*in-out*/ArtClassDefinition* def);
 
-  static jvmtiError RetransformClassesDirect(
+  static void RetransformClassesDirect(
       art::Thread* self,
       /*in-out*/std::vector<ArtClassDefinition>* definitions);