runtime-cleanup.tmpl: keep virtio-rng (#1179000)

Virtual machines easily get starved for randomness, and Anaconda insists
on sufficient amounts of entropy when the user requests LUKS disk
encryption. As a result, such installations can hang until Anaconda gives
up (after 10 minutes) and makes do with whatever entropy is available.

The virtualization host can feed randomness to the guest, unblocking the
installation. However, the guest can only consume that randomness through
the virtio-rng module. Let's not remove that module.

Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Brian C. Lane <bcl@redhat.com>

Resolves: rhbz#1179000
(cherry picked from commit bd501cccef)

share/runtime-cleanup.tmpl

@@ -91,7 +91,15 @@ arch/x86/kvm
 %endfor
 remove lib/modules/*/{build,source,*.map}
 ## Need to keep virtio_console.ko and ipmi stuff in drivers/char
-runcmd chroot ${root} find /lib/modules -regex ".*/kernel/drivers/char/.*" \! -name virtio_console.ko\* \! -name ipmi* -delete
+## Also keep virtio-rng so that the installer can get sufficient randomness for
+## LUKS setup.
+runcmd chroot ${root} find /lib/modules \
+                        -regex ".*/kernel/drivers/char/.*" \
+                        \! -name virtio_console.ko\* \
+                        \! -name hw_random \
+                        \! -name virtio-rng.ko\* \
+                        \! -name ipmi\* \
+                        -delete
 ## NOTE: depmod gets re-run after cleanup finishes
 
 ## remove unused themes, theme engines, icons, etc.