Moved groovy compilation phase from core to parent

Use stock gmaven plugin to achieve this

core/pom.xml

@@ -669,21 +669,6 @@ THE SOFTWARE.
           </archive>
         </configuration>
       </plugin>
-      <plugin>
-        <groupId>org.kohsuke.gmaven</groupId>
-        <artifactId>gmaven-plugin</artifactId>
-        <!-- version specified in grandparent pom -->
-        <executions>
-          <execution>
-            <goals>
-              <goal>generateStubs</goal>
-              <goal>compile</goal>
-              <goal>generateTestStubs</goal>
-              <goal>testCompile</goal>
-            </goals>
-          </execution>
-        </executions>
-      </plugin>
     </plugins>
   </build>
 

pom.xml

@@ -508,6 +508,21 @@ THE SOFTWARE.
           </execution>
         </executions>
       </plugin>-->
+      <plugin>
+        <groupId>org.codehaus.groovy.maven</groupId>
+        <artifactId>gmaven-plugin</artifactId>
+        <version>1.0</version>
+        <executions>
+          <execution>
+            <goals>
+              <goal>generateStubs</goal>
+              <goal>compile</goal>
+              <goal>generateTestStubs</goal>
+              <goal>testCompile</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
     </plugins>
 
   </build>