MT#6559 remove usage of CLASS

so in a future step we can remove this from
Sipwise::Base

lib/NGCP/Panel/Controller/Administrator.pm

@@ -290,7 +290,7 @@ sub api_key :Chained('base') :PathPart('api_key') :Args(0) {
     );
 }
 
-$CLASS->meta->make_immutable;
+__PACKAGE__->meta->make_immutable;
 
 __END__
 

lib/NGCP/Panel/Controller/Billing.pm

@@ -786,7 +786,7 @@ sub peaktime_specials_create :Chained('peaktimes_list') :PathPart('date/create')
     $c->stash(peaktimes_special_createflag => 1);
 }
 
-$CLASS->meta->make_immutable;
+__PACKAGE__->meta->make_immutable;
 
 1;