Fix off by one in OriginalNamePass check (#473)

Summary:
This PR fixes a bug in `strncmp("LX/", cls_type->get_name()->c_str(), 2)` where the size parameter should be 3. When it is 2 this call will miss checking for the `/` character.
Pull Request resolved: #473

Reviewed By: agampe

Differential Revision: D20996439

Pulled By: justinjhendrick

fbshipit-source-id: 3962186a387e71e9195e150d74db59149760ccc6

opt/original_name/OriginalNamePass.cpp

@@ -59,7 +59,7 @@ void OriginalNamePass::run_pass(DexStoresVector& stores,
   DexType* string_type = type::java_lang_String();
   for (const auto& it : to_annotate) {
     const DexType* cls_type = it.first;
-    if (strncmp("LX/", cls_type->get_name()->c_str(), 2) != 0) {
+    if (strncmp("LX/", cls_type->get_name()->c_str(), 3) != 0) {
       continue;
     }