Fixed a bug in the bias shift code where an expression was not being correctly calculated before being cast to an integer.
Fixed a bug in the bias shift code where an expression was not being correctly calculated before being cast to an integer.

git-svn-id: cc674101e2b794ddc2100b657215d55256e3fd48@15595 fe389314-cf27-0410-b35b-8c050e845b92

jhunkeler/hstcal,jhunkeler/hstcal,jhunkeler/hstcal