fix: set new clean-install instructions

Author: cuprumtan

packaging/rpm/SPECS/mamonsu.spec

@@ -65,12 +65,13 @@ touch /etc/mamonsu/plugins/__init__.py
 mkdir -p /var/log/mamonsu
 chown mamonsu.mamonsu /var/log/mamonsu
 
-chown mamonsu.mamonsu /etc/mamonsu/agent.conf
-
 %preun
 /sbin/service mamonsu stop >/dev/null 2>&1
 /sbin/chkconfig --del mamonsu
 
+%post
+chown mamonsu.mamonsu /etc/mamonsu/agent.conf
+
 %changelog
 * Mon Feb 21 2022 Alexandra Kuznetsova <[email protected]>  - 3.4.0-1
   - added Server Version metric;