rpm: correctly obsolete older rpm builds

The prior change in #268 didn't completely obsolete older builds of
gvisor-tap-vsock, causing installation conflicts with the official
Fedora builds. This commit should correctly obsolete fedora packages.

Ref: https://cirrus-ci.com/task/5730166412935168

Note: To avoid nvr complexity, this commit only fixes the conflicts for
official Fedora builds. Any issues with the podman-next copr can be
fixed on a case-by-case basis unless an overwhelming amount of people
complain.

Signed-off-by: Lokesh Mandvekar <[email protected]>

rpm/gvisor-tap-vsock.spec

@@ -70,6 +70,10 @@ dynamic port forwarding.
 %package gvforwarder
 Summary: %{desc_gvforwarder}
 Provides: gvforwarder = %{epoch}:%{version}-%{release}
+%if !%{defined copr_username}
+Obsoletes: %{name} < 6:0.7.0-6
+Recommends: %{name} = %{epoch}:%{version}-%{release}
+%endif
 
 %description gvforwarder
 %{desc_gvforwarder}