Create the proper init file in a distribution-agnostic way

From http://unix.stackexchange.com/a/164092/105389

plugins/00_dokku-standard/install

@@ -11,9 +11,8 @@ fi
 
 # temporary hack for https://github.com/dokku/dokku/issues/82
 # redeploys all apps after a reboot
-case "$DOKKU_DISTRO" in
-  ubuntu)
-    cat<<EOF > /etc/init/dokku-redeploy.conf
+if [[ $(/sbin/init --version 2> /dev/null) =~ upstart ]]; then
+  cat<<EOF > /etc/init/dokku-redeploy.conf
 description "Dokku app redeploy service"
 
 start on filesystem and started docker
@@ -23,10 +22,10 @@ script
   sudo -i -u dokku /usr/local/bin/dokku ps:restore
 end script
 EOF
-    ;;
+fi
 
-  debian|opensuse)
-    cat<<EOF > /etc/systemd/system/dokku-redeploy.service
+if [[ $(systemctl 2> /dev/null) =~ -\.mount ]]; then
+  cat<<EOF > /etc/systemd/system/dokku-redeploy.service
 [Unit]
 Description=Dokku app redeploy service
 After=docker.target
@@ -39,11 +38,10 @@ ExecStart=/usr/local/bin/dokku ps:restore
 [Install]
 WantedBy=multi-user.target
 EOF
-    if command -v systemctl &>/dev/null; then
-      systemctl enable dokku-redeploy
-    fi
-    ;;
-esac
+  if command -v systemctl &>/dev/null; then
+    systemctl enable dokku-redeploy
+  fi
+fi
 
 mkdir -p /etc/update-motd.d
 cat<<EOF > /etc/update-motd.d/99-dokku