[build] Fix docker organization parameter (apache#2597)

*Motivation*

docker orgnization is missing for building test image. so the build will be failing with `-Pdocker`.

*Changes*

Move the docker organization parameter to root pom file.

docker/pom.xml

@@ -31,9 +31,6 @@
   <groupId>org.apache.pulsar</groupId>
   <artifactId>docker-images</artifactId>
   <name>Apache Pulsar :: Docker Images</name>
-  <properties>
-    <docker.organization>apachepulsar</docker.organization>
-  </properties>
   <modules>
     <module>pulsar</module>
     <module>grafana</module>

pom.xml

@@ -132,6 +132,7 @@ flexible messaging model and an intuitive client API.</description>
     <redirectTestOutputToFile>true</redirectTestOutputToFile>
     <testRealAWS>false</testRealAWS>
     <testRetryCount>1</testRetryCount>
+    <docker.organization>apachepulsar</docker.organization>
 
     <!-- pin the protobuf-shaded version to make the pulsar build friendly to intellij -->
     <pulsar.protobuf.shaded.version>2.1.0-incubating</pulsar.protobuf.shaded.version>