[JENKINS-34751] updated Groovy to 2.4.7

follow-up for JENKINS-34751

(cherry picked from commit 96a78285)

core/pom.xml

@@ -41,7 +41,7 @@ THE SOFTWARE.
     <staplerFork>true</staplerFork>
     <stapler.version>1.243</stapler.version>
     <spring.version>2.5.6.SEC03</spring.version>
-    <groovy.version>2.4.6-jenkins-1</groovy.version>
+    <groovy.version>2.4.7</groovy.version>
   </properties>
 
   <dependencies>