rhel: bug fix upgrade path in kmod fedora spec file

rhel: bug fix upgrade path in kmod fedora spec file

This patch removes the "Conflicts" tag and adds "Obsoletes" tag.

With the conflicts tag, when a user attempts to install or upgrade with
the same version as already installed, the conflict kicks in. Otherwise,
such is allowed with --replacepkgs.

Obsoletes is needed for the upgrade path from kmod-openvswitch to
openvswitch-kmod.

Fixes: 22c33c3039 (rhel: support kmod build against mulitple kernel
versions, fedora)

VMware-BZ: #2249788

Signed-off-by: Martin Xu <martinxu9.ovs@gmail.com>
Signed-off-by: Greg Rose <gvrose8192@gmail.com>
Acked-by: Flavio Leitner <fbl@sysclose.org>
CC: Yi-Hung Wei <yihung.wei@gmail.com>
CC: Yifeng Sun <pkusunyifeng@gmail.com>
CC: Zak Whittington <zwhitt.vmware@gmail.com>
CC: Ben Pfaff <blp@ovn.org>
Signed-off-by: Ben Pfaff <blp@ovn.org>