Add ART -help and -showversion

Bug: https://code.google.com/p/android/issues/detail?id=62149
Change-Id: I5c21c0433f5f341f94e7d977e8d2d69cc46d6fe3
diff --git a/runtime/native/dalvik_system_VMRuntime.cc b/runtime/native/dalvik_system_VMRuntime.cc
index decbc66..d9bb121 100644
--- a/runtime/native/dalvik_system_VMRuntime.cc
+++ b/runtime/native/dalvik_system_VMRuntime.cc
@@ -155,7 +155,7 @@
 }
 
 static jstring VMRuntime_vmVersion(JNIEnv* env, jobject) {
-  return env->NewStringUTF(Runtime::Current()->GetVersion());
+  return env->NewStringUTF(Runtime::GetVersion());
 }
 
 static jstring VMRuntime_vmLibrary(JNIEnv* env, jobject) {