fragileUserData-apps might keep data on uninstall

If an app declares that is has flagile user data, all the user to choose
to keep the app-data on uninstall.

Test: Unistalled apps that set the new flag and app that did not.
      Verified that the KEEP_DATA flag was set when checkbox was
      clicked.
Change-Id: I032fb21854352bbc175934ae5eb68a1430b1d403
Fixes: 117578306