update gradle wrapper to 2.3

Author: geminiwen

gradle/wrapper/gradle-wrapper.jar

@@ -1,6 +1,6 @@
-#Sat Jun 28 18:37:32 CST 2014
+#Mon May 04 10:06:37 CST 2015
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=http\://services.gradle.org/distributions/gradle-2.2.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-2.3-bin.zip