solve PHP Warning

git-svn-id: https://plugins.svn.wordpress.org/woocomerce-price-by-country/trunk@1007354 b8457f37-d9ea-0310-8a92-e5e31aec5664
solved naming function of pbc_remove_loop_button

git-svn-id: https://plugins.svn.wordpress.org/woocomerce-price-by-country/trunk@1007361 b8457f37-d9ea-0310-8a92-e5e31aec5664