BasicSyncAdapter Sample: Update gradle wrapper version

Switch from v1.6 to v1.8.

Change-Id: I7750f40c8eb3a82af36dc7f8586fd0c2f8a48d77
diff --git a/connectivity/sync/BasicSyncAdapter/gradle/wrapper/gradle-wrapper.properties b/connectivity/sync/BasicSyncAdapter/gradle/wrapper/gradle-wrapper.properties
index 5c22dec..861eddc 100644
--- a/connectivity/sync/BasicSyncAdapter/gradle/wrapper/gradle-wrapper.properties
+++ b/connectivity/sync/BasicSyncAdapter/gradle/wrapper/gradle-wrapper.properties
@@ -3,4 +3,4 @@
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=http\://services.gradle.org/distributions/gradle-1.6-bin.zip
+distributionUrl=http\://services.gradle.org/distributions/gradle-1.8-bin.zip