libs/rpms : update for CentOS 7 removal

With the removal of CentOS 7, we can re-evaluate the rpm
installations.

We should not need virtualenv after https://review.opendev.org/712609

There should be no need for python-devel as we're python3

pyOpenSSL was added to workaround memory issues in
9e98f9435ec36f2fffed0ac368befd520f07e0e1 (2015) ... I think we've
moved on.

pyxattr is not a package; remove it.

I don't see we need packaged m2crypto, which isn't a package on CentOS
8.  nor libxml2-python; these days it has wheels which should work
with the normal installation process.

centos8 has:

 * targetcli
 * pcp-system-tools (and no dstat)
 * iptables-services
 * java-1.8.0-openjdk-headless
 * kernel-modules
 * rsync-daemon

just as all supported fedora's do, so we can remove any matching here.

Change-Id: I542c426a67a98f331d2a29bacd220af81fab8cc4
diff --git a/files/rpms/nova b/files/rpms/nova
index 0f3d10f..2218330 100644
--- a/files/rpms/nova
+++ b/files/rpms/nova
@@ -7,12 +7,8 @@
 genisoimage # required for config_drive
 iptables
 iputils
-kernel-modules # dist:f30,f31
+kernel-modules
 kpartx
-libxml2-python
-m2crypto
-mysql-devel
-mysql-server # NOPRIME
 parted
 polkit
 rabbitmq-server # NOPRIME