PHP samples fixes

@smashwilson I like the idea of instantiating a `$loadBalancer` object first (to provide context) but because no other sample does this, I followed convention. I wanted to make sure that the PHP sample was similar in approach to all the others. Plus, the user will need to plug in the ID anyway. What do you recommend me to do - create a `$loadBalancer` variable or leave this sample as it is?