Makefile: Add the missing library in otatools.zip.

With the change in [1], delta_generator now needs
libprotobuf-cpp-lite.so instead of libprotobuf-cpp-lite-rtti.so to
generate A/B payloads.

[1] commit ab5bd668f6be600a8cceb8772e426c0aa902a5e1

Bug: 27145830
Change-Id: Ib9a93bf0fbe7fa44fc5fb94668d17fa1a2e07b05