JOSM-Warning at source:maxspeed=DE:zone:20

[Rainero]

What steps will reproduce the problem?

1. Load card at ​https://www.openstreetmap.org/way/12095259
2. Run "Prüfung" in JOSM

What is the expected result?

JOSM should not throw a warning, because zones with 20 km/h limit exist in DE.

What happens instead?

JOSM shows a warning. If it is source:maxspeed=DE:zone:30, there is no warning.
In my opinion source:maxspeed=DE:zone would be sufficient, if maxspeed is set, but the wiki allows DE:zone, DE:zone30 and DE:zone:30, so it should be okay also if the speed is 20.

Please provide any additional information below. Attach a screenshot if possible.

URL:http://josm.openstreetmap.de/svn/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2017-12-31 03:09:43 +0100 (Sun, 31 Dec 2017)
Build-Date:2017-12-31 02:33:46
Revision:13265
Relative:URL: ^/trunk

Identification: JOSM/1.5 (13265 de) Linux openSUSE 12.2 (x86_64)
Memory Usage: 926 MB / 1758 MB (420 MB allocated, but free)
Java version: 1.8.0_101-b13, Oracle Corporation, Java HotSpot(TM) 64-Bit Server VM
Screen: :0.0 1280x1024
Maximum Screen Size: 1280x1024
Dataset consistency test: No problems found

Plugins:
+ OpeningHoursEditor (33876)
+ buildings_tools (33735)
+ contourmerge (1032)
+ editgpx (33782)
+ pt_assistant (33860)
+ reverter (33865)
+ terracer (33839)
+ turnlanes (33858)
+ turnrestrictions (33780)
+ utilsplugin2 (33742)

Tagging presets:
+ http://www.openrailwaymap.org/josm-presets/de-signals-bostrab.zip
+ http://www.openrailwaymap.org/josm-presets/de.zip
+ http://www.openrailwaymap.org/josm-presets/de-signals-eso.zip
+ https://josm.openstreetmap.de/josmfile?page=Presets/PublicTransportOneClick&zip=1

Map paint styles:
- https://josm.openstreetmap.de/josmfile?page=Styles/Maxspeed&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Styles/Lit&zip=1
- http://www.openrailwaymap.org/styles/josm-additional.zip
- http://www.openrailwaymap.org/styles/electrified.zip
- http://www.openrailwaymap.org/styles/standard.zip
- http://www.openrailwaymap.org/styles/maxspeed.zip
- http://www.openrailwaymap.org/styles/signals.zip
- https://josm.openstreetmap.de/josmfile?page=Styles/PublicTransport&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/LessObtrusiveNodes&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/ShowID&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/PublicTransportV2&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/MaxspeedIcons&zip=1

Last errors/warnings:
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet

[Don-vip]

In 13348/josm:

fix #15803 - don't issue a warning for source:maxspeed=*:zone:20