Upgrade to Groovy 2.4.17

Closes gh-16836

Author: snicoll

spring-boot-dependencies/pom.xml

@@ -78,7 +78,7 @@
 		<gemfire.version>8.2.13</gemfire.version>
 		<glassfish-el.version>3.0.0</glassfish-el.version>
 		<gradle.version>2.9</gradle.version>
-		<groovy.version>2.4.16</groovy.version>
+		<groovy.version>2.4.17</groovy.version>
 		<gson.version>2.8.5</gson.version>
 		<h2.version>1.4.199</h2.version>
 		<hamcrest.version>1.3</hamcrest.version>