Change ByteContainer::to_hex for clang debug mode (#401)
Change ByteContainer::to_hex for clang debug mode (#401)

In clang debug mode (_GLIBCXX_DEBUG), the operator[] for std::vector
performs some bound checking, which caused ByteContainer::to_hex to
segfault.
hanw/behavioral-model,p4lang/behavioral-model,hanw/behavioral-model,p4lang/behavioral-model,hanw/behavioral-model,p4lang/behavioral-model,hanw/behavioral-model,p4lang/behavioral-model,p4lang/behavioral-model,hanw/behavioral-model