Upgrade build to Gradle 2.4

Issue: SPR-12772

Author: sbrannen

build.gradle

@@ -1338,7 +1338,7 @@ configure(rootProject) {
 
 	task wrapper(type: Wrapper) {
 		description = "Generates gradlew[.bat] scripts"
-		gradleVersion = "2.2.1"
+		gradleVersion = "2.4"
 
 		doLast() {
 			def gradleOpts = "-XX:MaxMetaspaceSize=1024m -Xmx1024m"

gradle/wrapper/gradle-wrapper.jar

@@ -1,6 +1,6 @@
-#Mon Jan 05 09:59:07 CET 2015
+#Wed May 06 21:35:37 CEST 2015
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-2.2.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-2.4-bin.zip