Make ART fail gracefully when it can't update the desired code.

ART was exiting with a fatal error when it couldn't clean an obsolete
file. Relaxing this and failing gracefully preserves the behaviour that
Dalvik had.

Bug: 15313272
Change-Id: I8d0d6d374c90d2a434909dd4ae56f0799f30134d
diff --git a/runtime/class_linker.h b/runtime/class_linker.h
index d9b3d25..64bffc9 100644
--- a/runtime/class_linker.h
+++ b/runtime/class_linker.h
@@ -571,7 +571,8 @@
   const OatFile* FindOatFileContainingDexFileFromDexLocation(const char* location,
                                                              const uint32_t* const location_checksum,
                                                              InstructionSet isa,
-                                                             std::vector<std::string>* error_msgs)
+                                                             std::vector<std::string>* error_msgs,
+                                                             bool* obsolete_file_cleanup_failed)
       LOCKS_EXCLUDED(dex_lock_, Locks::mutator_lock_);
 
   // Find a verify an oat file with the given dex file. Will return nullptr when the oat file