[form] fix #719285, due to multiple calls to restore_previous_post, by proper refactorings * move __init__ code from FieldsForm to Form. Must behaviour here should actually be in the Form base class * avoid buggy duplicated call to restore_previous_post * move some code that was in the form renderer to the form'__init__ method (__redirectpath & __form_id hidden input handling)) * 'formvid' should now be specified on form selection, not on form rendering

/var/log/cubicweb/*.log {
        weekly
        missingok
        rotate 10
        compress
        delaycompress
        notifempty
        create 640 root adm
        sharedscripts
        postrotate
           if [ -x /usr/sbin/invoke-rc.d ]; then \
              invoke-rc.d cubicweb reload > /dev/null; \
           else \
              /etc/init.d/cubicweb reload > /dev/null; \
           fi; \
        endscript
}