Avoid warning noise in logrotate.get

There is no guarantee that a lookup failure is necessarily a problem,
so presenting a message to this effect as a warning has led to
confusion for some (and annoyance for others). This resolves the issue
by showing the message at the debug level.

Fixes saltstack#53988

salt/modules/logrotate.py

@@ -159,7 +159,7 @@ def get(key, value=None, conf_file=_DEFAULT_CONF):
     if value:
         if stanza:
             return stanza.get(value, False)
-        _LOG.warning("Block '%s' not present or empty.", key)
+        _LOG.debug("Block '%s' not present or empty.", key)
     return stanza