publishers/join-trigger: advertise "threshold" in the docs

The join-trigger documentation still uses the deprecated
"even-if-unstable" field in its examples.

Update the "join-trigger001.yaml" fixture referenced by the
documentation to use the "threshold" configuration instead.

Add a new fixture to retain coverage for "even-if-unstable".

Change-Id: Ic8b28b384e0a6d7e43833d2db9524a41e4508ba7

tests/publishers/fixtures/join-trigger001.xml

@@ -27,7 +27,11 @@
           </configs>
         </hudson.plugins.parameterizedtrigger.BuildTrigger>
       </joinPublishers>
-      <evenIfDownstreamUnstable>true</evenIfDownstreamUnstable>
+      <resultThreshold>
+        <name>UNSTABLE</name>
+        <ordinal>1</ordinal>
+        <color>YELLOW</color>
+      </resultThreshold>
     </join.JoinTrigger>
   </publishers>
 </project>

tests/publishers/fixtures/join-trigger001.yaml

@@ -3,7 +3,7 @@ publishers:
       projects:
         - project-one
         - project-two
-      even-if-unstable: true
+      threshold: unstable
       publishers:
         - trigger-parameterized-builds:
           - project: archive

tests/publishers/fixtures/join-trigger003.xml

@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="utf-8"?>
+<project>
+  <publishers>
+    <join.JoinTrigger>
+      <joinProjects>project-one,project-two</joinProjects>
+      <joinPublishers>
+        <hudson.plugins.parameterizedtrigger.BuildTrigger>
+          <configs>
+            <hudson.plugins.parameterizedtrigger.BuildTriggerConfig>
+              <configs>
+                <hudson.plugins.parameterizedtrigger.CurrentBuildParameters/>
+              </configs>
+              <projects>archive</projects>
+              <condition>ALWAYS</condition>
+              <triggerFromChildProjects>true</triggerFromChildProjects>
+              <triggerWithNoParameters>true</triggerWithNoParameters>
+            </hudson.plugins.parameterizedtrigger.BuildTriggerConfig>
+            <hudson.plugins.parameterizedtrigger.BuildTriggerConfig>
+              <configs>
+                <hudson.plugins.parameterizedtrigger.CurrentBuildParameters/>
+              </configs>
+              <projects>cleanup</projects>
+              <condition>ALWAYS</condition>
+              <triggerFromChildProjects>false</triggerFromChildProjects>
+              <triggerWithNoParameters>false</triggerWithNoParameters>
+            </hudson.plugins.parameterizedtrigger.BuildTriggerConfig>
+          </configs>
+        </hudson.plugins.parameterizedtrigger.BuildTrigger>
+      </joinPublishers>
+      <evenIfDownstreamUnstable>true</evenIfDownstreamUnstable>
+    </join.JoinTrigger>
+  </publishers>
+</project>

tests/publishers/fixtures/join-trigger003.yaml

@@ -0,0 +1,15 @@
+publishers:
+  - join-trigger:
+      projects:
+        - project-one
+        - project-two
+      even-if-unstable: true
+      publishers:
+        - trigger-parameterized-builds:
+          - project: archive
+            current-parameters: true
+            trigger-from-child-projects: true
+            trigger-with-no-params: true
+          - project: cleanup
+            current-parameters: true
+            trigger-with-no-params: false