Remove RRD4J from default installation

openhab/openhab-webui#1659 added recommended
addons to the setup wizard. 
These will get installed on a new openHAB install if the user does not
actively de-select them, so the RRD4J installation from the distro is
not required anymore.

See also openhab#1455.

Signed-off-by: Florian Hotze <florianh_dev@icloud.com>

distributions/openhab/src/main/resources/conf/services/addons.cfg

@@ -1,7 +1,7 @@
 # The installation package of this openHAB instance
 #
 # Valid options:
-#   - standard : Standard setup for normal use of openHAB with persistence (rrd4j) and additional UI add-ons (basic,habpanel).
+#   - standard : Standard setup for normal use of openHAB with additional UI add-ons (basic,habpanel).
 #   - minimal  : Installation of core components without additional add-ons.
 #
 # Note: The add-ons in the installation package are only installed at the VERY FIRST START of openHAB

features/distro/src/main/feature/feature.xml

@@ -14,7 +14,6 @@
         <config name="org.openhab.addons" append="true">
 			package = standard
 			ui = basic,habpanel
-			persistence = rrd4j
         </config>
     </feature>