Fixed qnet error that occurred when using relative paths by reverting to...

Fixed qnet error that occurred when using relative paths by reverting to storing relative paths for Cube Viewports. Fixes #5177

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@8256 41f8697f-d340-4b68-9986-7bafba869bb8