kvm: Remove dupplicate extends

software/kvm/common.cfg

@@ -4,19 +4,14 @@ extends =
   ../../component/6tunnel/buildout.cfg
   ../../component/curl/buildout.cfg
   ../../component/dash/buildout.cfg
-  ../../component/dcron/buildout.cfg
-  ../../component/gzip/buildout.cfg
   ../../component/qemu-kvm/buildout.cfg
-  ../../component/logrotate/buildout.cfg
   ../../component/noVNC/buildout.cfg
   ../../component/openssl/buildout.cfg
-  ../../component/dcron/buildout.cfg
   ../../component/netcat/buildout.cfg
   ../../component/pycurl/buildout.cfg
   ../../stack/slapos.cfg
   ../../stack/nodejs.cfg
   ../../stack/resilient/buildout.cfg
-  ../../stack/monitor/buildout.cfg
   ../../stack/logrotate/buildout.cfg
 
 # stacks are listed from most generic to most specific,