[FLINK-3067] Enforce zkclient 0.7 for Kafka

This closes #1399

flink-streaming-connectors/flink-connector-kafka/pom.xml

@@ -92,6 +92,14 @@ under the License.
 			</exclusions>
 		</dependency>
 
+		<!-- force using the latest zkclient -->
+		<dependency>
+			<groupId>com.101tec</groupId>
+			<artifactId>zkclient</artifactId>
+			<version>0.7</version>
+			<type>jar</type>
+		</dependency>
+
 		<dependency>
 			<groupId>com.google.guava</groupId>
 			<artifactId>guava</artifactId>
@@ -124,6 +132,7 @@ under the License.
 		</dependencies>
 	</dependencyManagement>
 	
+
 	<build>
 		<plugins>
 			<plugin>