MDL-12718 show the print_header navigation warning only if in DEBUG_DEVELOPER mode; merged from MOODLE_19_STABLE

lib/weblib.php

@@ -2321,7 +2321,7 @@ function print_header ($title='', $heading='', $navigation='', $focus='',
 
     if (gettype($navigation) == 'string' && strlen($navigation) != 0 && $navigation != 'home') {
         debugging("print_header() was sent a string as 3rd ($navigation) parameter. "
-                . "This is deprecated in favour of an array built by build_navigation(). Please upgrade your code.");
+                . "This is deprecated in favour of an array built by build_navigation(). Please upgrade your code.", DEBUG_DEVELOPER);
     }
 
     $heading = format_string($heading); // Fix for MDL-8582
@@ -7056,6 +7056,5 @@ function is_in_popup() {
 }
 
 
-
 // vim:autoindent:expandtab:shiftwidth=4:tabstop=4:tw=140:
 ?>