svr4pkg now supports the installation only in the current zone (-G switch for pkgadd)

By standard, pkgadd adds an package in the global zones and all non-global zones. But with an configuration management, you maybe dont want to have this behavior. pkgadd supports the -G switch, which triggers an installation only in the current zone. This pullrequest enables this switch for the package svr4pkg and sets this switch as default behaviour.