Remote building for iOS and tvOS does not properly remove files from previous builds causing compile failures

Remote building for iOS/tvOS is leaving behind generated files which can cause various compile issues when creating different projects in different streams with the same name (MyProject, MyProject1, etc...)

Example bug: UE-43085

After hitting the compile errors I went onto the Remote Mac and cleared out the Remote Builds folder and was able to package successfully. See attached log for compile errors and then successful build after cleaning the remote mac.

This message can be seen in the log:

[2017.03.21-17.33.59:060][440]UATHelper: Packaging (tvOS): UnrealBuildTool: IO error encountered -- skipping file deletion

1. Create a new project
2. Setup Remote Building options for iOS in PRoject Settings -> iOS -> Remote Building
3. Package for tvOS in Development Config
4. Once packaging is complete, package for tvOS again.

Result: IO error shown in log for removing files
Expected: Files from previous builds are removed