nvmetcli: add python-six to rpm package building

From experience, if python-six isn't installed on a Fedora
system, hard-to-decipher errors can occur trying to use
nvmetcli.

Signed-off-by: Jay Freyensee <james.p.freyensee@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

rpm/nvmetcli.spec.tmpl

@@ -9,7 +9,7 @@ Source:         nvmetcli-%{version}.tar.gz
 BuildRoot:      %{_tmppath}/%{name}-%{version}-%{release}-rpmroot
 BuildArch:      noarch
 BuildRequires:  python-devel python-setuptools systemd-units
-Requires:	python-configshell python-kmod
+Requires:	python-configshell python-kmod python-six
 Requires(post): systemd
 Requires(preun): systemd
 Requires(postun): systemd