PROG: Added history entry for fix to oblique detector resolution formula in...

PROG:  Added history entry for fix to oblique detector resolution formula in the Camera class.  References #4614.

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@7567 41f8697f-d340-4b68-9986-7bafba869bb8