Fix Mac integration tests: don't append a line to Firestore core cmake file in build_desktop.py (#242)
Fix Mac integration tests: don't append a line to Firestore core cmake file in build_desktop.py (#242)

* Remove append from build_desktop.py as it breaks things on Mac.
firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk