Code tidy up

The actual code change in this is to slightly reduce the extent by which arrays are passed by reference & variables are set with unknown implications

In this case the variables involved are

$form_>_values['contribution_id'] 
$form_values['cc_recur']

I couldn't find evidence of the second being used & the first doesn't seem to be set when called from a membership context & the other time it is called is right at the end of the post_process hook.

I guess there is some risk postProcess hooks could rely on it though? but then ??????