scripts/installer/README_ipp-os-shutdown.adoc: fix asciidoc list style

Signed-off-by: Jim Klimov <jimklimov@gmail.com>

Author: jimklimov

scripts/installer/common/README_ipp-os-shutdown.adoc

@@ -53,6 +53,7 @@ which can invoke a customized copy of `ipp-host-shutdown.sample` script
 for host-specific procedures (such as clusterware shutdown).
 
 The `ipp-os-shutdown` script has several roles:
+
 * it manages the delayed shutdown (which can be canceled before the timer
 expires, and can not be aborted after the timer expires - so it proceeds
 to the end)