Version numbers are printed inconsistently

Most of the BIND utilities report their version number to stderr. A few print to stdout instead: named, named-checkconf, named-checkzone. The utilities that print to stderr then exit(0), so they disagree with themselves about whether reporting the version number is an error or not. Since the user asked for the version number it seems more logical to make it a non-error, i.e. print to stdout and exit(0).