With c++17, std::optional provides the functionality that Maybe
provided.
Bug: 183215655
Test: aapt2_tests
Change-Id: I62bb9c2fa4985dc5217a6ed153df92b85ad9a034
Without a FinishEntry call, the file_ wasn't being released, which
prevents another StartEntry from succeeding.
Bug: 68033366
Test: manual aapt2 link --output-to-dir -o outputDir
Test: Archive_test.cpp
Change-Id: I3b66266327163307a2e4c7f891f6ee76baf7fc10