appman wipes PWD after PackageManager.startPackageInstallation()

Steps to reproduce

1. On your dev PC, extract the attached project to a new directory ("APPROOT")
2. From the console, cd into <APPROOT>
3. Run `appman -c am-config.yaml`
4. Click the "Install" button in the GUI
5. Close the GUI window
6. Run `appman -c am-config.yaml` again

Outcomes

• After Step #4, the package is installed into <APPROOT>/apps/animated-windows.rabbit/ (This is expected)
• After Step #4, an empty directory is created at <APPROOT>/animated-windows.rabbit/ (This is NOT expected)
• After Step #6, the contents of <APPROOT> get deleted and appman fails to load main.qml (This is NOT expected)

Notes

• If Step #4 is skipped, then nothing gets deleted
• If we cd into <APPROOT>/apps/ and run "appman -c ../am-config.yaml" instead, then nothing gets deleted