[BUGFIX] Deactivate zend_extension line inside the config

This fixes a warning that the extension is already loaded.

templates/default/xdebug.ini.erb

 ; Generated automatically by Chef
 ; (see https://github.com/derickr/xdebug/blob/master/xdebug.ini for more information)
 
-zend_extension = <%= Mixlib::ShellOut.new("php -i | grep extension_dir | awk 'NR==1 {print $(NF)}'").run_command.stdout.strip %>/xdebug.so
+;zend_extension = <%= Mixlib::ShellOut.new("php -i | grep extension_dir | awk 'NR==1 {print $(NF)}'").run_command.stdout.strip %>/xdebug.so
 
 ; -----------------------------------------------------------------------------
 ; xdebug.auto_trace