Upgrade Gradle Wrapper version to Gradle 2.12

Issue: SPR-14048

Author: sbrannen

build.gradle

@@ -1375,7 +1375,7 @@ configure(rootProject) {
 
 	task wrapper(type: Wrapper) {
 		description = "Generates gradlew[.bat] scripts"
-		gradleVersion = "2.10"
+		gradleVersion = "2.12"
 
 		doLast() {
 			def gradleOpts = "-XX:MaxMetaspaceSize=1024m -Xmx1024m"