adb: fix mistaken uses of SendFail in file_sync_service.cpp.

SendFail and SendSyncFail are similarly named, and have the same
prototype. Use `#pragma GCC poison` to prevent use of SendFail in
file_sync_service.cpp, and fix the places where it was used
accidentally.

Change-Id: I6b9a7e565b76dfab10f8ae38f889d046ad80a403