waht is stated in the Qatar Labor Law that company can terminate an employee without giving any reason as long as they observe the notice period?

What you are saying is easier said than done!  And you want the labor attache to handle this case?  It's like asking for the moon to shine during daytime!

Do you honestly believe that the OP will go such scenario? How I wish! 

And if there is a law trhat governs everything, why do you need for a contract?