Obsolete zram package from zram-generator-defaults

It doesn't make much sense to have both zram-generator-defaults and zram
installed at the same time. It's likely to only lead to user confusion.

Also approved in https://fedoraproject.org/wiki/Changes/SwapOnZRAM#Scope.

rust-zram-generator.spec

@@ -5,7 +5,7 @@
 
 Name:           rust-%{crate}
 Version:        0.2.0
-Release:        2%{?dist}
+Release:        3%{?dist}
 Summary:        Systemd unit generator for zram swap devices
 
 # Upstream license specification: MIT
@@ -53,6 +53,7 @@ Recommends:     /usr/bin/zramctl
 %package     -n %{crate}-defaults
 Summary:        Default configuration for %{crate}
 Requires:       %{crate} = %{version}-%{release}
+Obsoletes:      zram < 0.4-2
 BuildArch:      noarch
 
 %description -n %{crate}-defaults
@@ -117,6 +118,9 @@ install -Dpm0644 -t %{buildroot}%{_mandir}/man5 man/zram-generator.5
 %endif
 
 %changelog
+* Sat Aug  1 2020 Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl> - 0.2.0-3
+- Obsolete zram package from zram-generator-defaults
+
 * Wed Jul 29 2020 Fedora Release Engineering <releng@fedoraproject.org> - 0.2.0-2
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_33_Mass_Rebuild