Wrap executePacket.toPacket(1) call with try/catch

This is to provide more context to error messages when a parameter is undefined.

Author: swftvsn

lib/commands/execute.js

@@ -50,7 +50,11 @@ Execute.prototype.start = function(packet, connection) {
     this.parameters,
     connection.config.charsetNumber
   );
-  connection.writePacket(executePacket.toPacket(1));
+  try {
+    connection.writePacket(executePacket.toPacket(1));
+  } catch (error) {
+    this.onResult(error)
+  }
   return Execute.prototype.resultsetHeader;
 };