Fix: broken skip slave error functionality

libraries/replication_gui.lib.php:908
function PMA_handleControlRequest()
checks for
if (isset($_REQUEST['sr_take_action']))
libraries/replication_gui.lib.php:202
but sr_take_action variable isn't included in $slave_skip_error_link generation

Signed-off-by: Igor Prokopenkov <cmyk777@gmail.com>