Allow for pkgname.x86_64 to be used in pkg states

This pull request allows for one to specify a package name ``zsh.x86_64`` on a RHEL-based system, and have it be properly recognized as just ``zsh`` by the state.

This allows the package name to match the output of ``pkg.list_pkgs``, keeping a package state with a target of ``zsh.x86_64`` from failing despite success in installing the package.

Fixes #7306.