Fix stack trace when encountering a checkstyle error

Change-Id: If1b7edd9aaf1779251b339dbef254fcc1b0e4690
diff --git a/tools/build/conf/src/main/java/org/onosproject/buckdaemon/BuckDaemon.java b/tools/build/conf/src/main/java/org/onosproject/buckdaemon/BuckDaemon.java
index 56deadd..f3166b1 100644
--- a/tools/build/conf/src/main/java/org/onosproject/buckdaemon/BuckDaemon.java
+++ b/tools/build/conf/src/main/java/org/onosproject/buckdaemon/BuckDaemon.java
@@ -175,7 +175,11 @@
             try {
                 try {
                     socket.setSoTimeout(1_000); //reads should time out after 1 second
-                    BuckTaskContext context = new BuckTaskContext(socket.getInputStream());
+                    BuckTaskContext context = BuckTaskContext.createBuckTaskContext(socket.getInputStream());
+                    if (context == null) {
+                        socket.close();
+                        return;
+                    }
 
                     String taskName = context.taskName();
                     BuckTask task = tasks.get(taskName);