deb rpm: remove manual feature of zero-downtime-restart from uninstall phase (#758)

We were going to support two methods of downgrading with zero downtime.

1. Running v6.x => Install v5.x package by overwriting
2. Running v6.x => Replace `FLUENT_PACKAGE_SERVICE_RESTART` value to
`manual` => uninstall v6.x => Install v5.x

The second method is to keep the Fluentd process running after
uninstalling it.
We decided to remove `2.` method because it may cause confusion for
users.

Signed-off-by: Shizuo Fujita <fujita@clear-code.com>

Author: Watson1978

fluent-package/templates/package-scripts/fluent-package/deb/prerm

@@ -33,18 +33,6 @@ esac
 # dh_installdeb will replace this with shell code automatically
 # generated by other debhelper scripts.
 
-. /etc/default/<%= service_name %>
-if [ "$FLUENT_PACKAGE_SERVICE_RESTART" = "manual" ]; then
-    # Do not stop service because removing package will be executed
-    # for major downgrade (e.g. uninstall v6 then reinstall v5)
-    # In such a case, missing plugins for v5 cause trouble in
-    # restarting service.
-    # so instead of restarting service here, demand users to install
-    # such plugins in advance then delegate users to restart service
-    # manually later.
-    :
-else
-    #DEBHELPER#
-fi
+#DEBHELPER#
 
 exit 0

fluent-package/yum/fluent-package.spec.in

@@ -197,18 +197,7 @@ if [ $1 -eq 2 ]; then
 fi
 
 %preun
-. %{_sysconfdir}/sysconfig/@SERVICE_NAME@
-echo "preun FLUENT_PACKAGE_SERVICE_RESTART: $FLUENT_PACKAGE_SERVICE_RESTART"
-if [ $1 -eq 0 ]; then
-  if [ "$FLUENT_PACKAGE_SERVICE_RESTART" = "manual" ]; then
-    # When rollback to previous version, there is a case that user want to
-    # restart manually to reduce downtime.
-    :
-  else
-    # disable service here
-    %systemd_preun @SERVICE_NAME@.service
-  fi
-fi
+%systemd_preun @SERVICE_NAME@.service
 
 %post
 . %{_sysconfdir}/sysconfig/@SERVICE_NAME@