Fixes broken commit

lib/Slic3r.pm

@@ -15,9 +15,9 @@ sub debugf {
 }
 
 # load threads before Moo as required by it
+use Config;
 our $have_threads = $Config{useithreads} && eval "use threads; use Thread::Queue; 1";
 
-use Config;
 use Moo;
 use Slic3r::Config;
 use Slic3r::ExPolygon;