Remove Fedora/libvirt workaround

An updated libvirt package to address [1] is in Fedora 20 now, so we
don't need this work-around.  Modify the comments of the other part of
the work-around (restart of services) and link to the most relevant
bug

[1] https://bugzilla.redhat.com/show_bug.cgi?id=1098376

Change-Id: I47fba7b4f273162c2af1e37902a512041449750b

lib/nova_plugins/functions-libvirt

@@ -29,19 +29,10 @@ function install_libvirt {
         install_package python-libguestfs
     fi
 
-    # workaround for
-    # https://bugzilla.redhat.com/show_bug.cgi?id=1098376; if we see
-    # the empty Xen proc file then remove the xen/libxl plugin
-    # shared-libraries (yum remove would uninstall libvirt due to
-    # dependencies, so let's avoid that...)
-    if is_fedora && [ -f /proc/xen/capabilities ] && \
-        [ $(stat -c '%s' /proc/xen/capabilities) -eq 0 ]; then
-        sudo rm -f /usr/lib64/libvirt/connection-driver/libvirt_driver_libxl.so
-        sudo rm -f /usr/lib64/libvirt/connection-driver/libvirt_driver_xen.so
-
-        # another bug requires these to be restarted to avoid
-        # potential hang of libvirtd
-        # https://bugzilla.redhat.com/show_bug.cgi?id=1098866
+    # Restart dbus/firewalld after install of libvirt to avoid a
+    # problem with polkit, which libvirtd brings in.  See
+    # https://bugzilla.redhat.com/show_bug.cgi?id=1099031
+    if is_fedora; then
         sudo service dbus restart
         sudo service firewalld restart
     fi