Obsolete earlier packages due to version bump

In order for package managers such as dnf to upgrade cleanly after
the package SONAME bump the obsolete package names must be known.
Update the new packages to correctly obsolete the old ones.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes openzfs#11844

rpm/generic/zfs.spec.in

@@ -166,6 +166,7 @@ This package contains the core ZFS command line utilities.
 Summary:        Native ZFS pool library for Linux
 Group:          System Environment/Kernel
 Obsoletes:      libzpool2
+Obsoletes:      libzpool4
 
 %description -n libzpool5
 This package contains the zpool library, which provides support
@@ -211,6 +212,7 @@ This library provides a variety of compatibility functions for OpenZFS:
 Summary:        Native ZFS filesystem library for Linux
 Group:          System Environment/Kernel
 Obsoletes:      libzfs2
+Obsoletes:      libzfs4
 
 %description -n libzfs5
 This package provides support for managing ZFS filesystems