Had to revert the change to get rid of the conservative case error message...

Had to revert the change to get rid of the conservative case error message because it cause negative planetary curvature - I expanded the error message

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@3423 41f8697f-d340-4b68-9986-7bafba869bb8