contrib/rpm: drop explicit dependency on libnl3 package

We already get a library dependency on

    libnl-3.so.200()(64bit)
    libnl-3.so.200(libnl_3)(64bit)

Drop the explicit package dependency, leaving only the
BuildRequires.

Also, all recent versions of libnl3 implement library versioning.

contrib/fedora/rpm/NetworkManager.spec

@@ -92,7 +92,6 @@ Requires(postun): systemd
 
 Requires: dbus >= %{dbus_version}
 Requires: glib2 >= %{glib2_version}
-Requires: libnl3 >= %{libnl3_version}
 Requires: %{name}-libnm%{?_isa} = %{epoch}:%{version}-%{release}
 Obsoletes: dhcdbd
 Obsoletes: NetworkManager < %{obsoletes_device_plugins}