Updated import work orders so that when undone, their items are removed from...

Updated import work orders so that when undone, their items are removed from project tree. Fixes #4597.

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/branches/ipce_FY17-Sprint1@7624 41f8697f-d340-4b68-9986-7bafba869bb8