Disable Connection Keep-Alive from Client Helper

On windows, client helper connections are terminated in a matter which
yields ugly exceptions on the server (java.io.IOException: An existing
connection was forcibly closed by the remote host).

Disabling keep-alive on the client helper connections elminates the
exceptions

Change-Id: I45aeed8a77a1853e2c54a6fff47d941da5ad8413
Reviewed-on: https://asterix-gerrit.ics.uci.edu/1639
Sonar-Qube: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Tested-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
BAD: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Reviewed-by: Till Westmann <tillw@apache.org>
diff --git a/asterixdb/asterix-client-helper/src/main/java/org/apache/asterix/clienthelper/commands/RemoteCommand.java b/asterixdb/asterix-client-helper/src/main/java/org/apache/asterix/clienthelper/commands/RemoteCommand.java
index e7b6be3..6a16761 100644
--- a/asterixdb/asterix-client-helper/src/main/java/org/apache/asterix/clienthelper/commands/RemoteCommand.java
+++ b/asterixdb/asterix-client-helper/src/main/java/org/apache/asterix/clienthelper/commands/RemoteCommand.java
@@ -73,6 +73,7 @@
         conn.setConnectTimeout(timeoutMillis);
         conn.setReadTimeout(timeoutMillis);
         conn.setRequestMethod(method.name());
+        conn.setRequestProperty("Connection", "close");
         return conn;
     }
 }