edit amazing post widget line 194-195, change to '', previously '0', due to a bug, when use siteorigin page builder, always return to default after saving the post.

git-svn-id: https://plugins.svn.wordpress.org/amazing-post-widget/trunk@794608 b8457f37-d9ea-0310-8a92-e5e31aec5664
change Tested up to 3.7 statement 

git-svn-id: https://plugins.svn.wordpress.org/amazing-post-widget/trunk@794609 b8457f37-d9ea-0310-8a92-e5e31aec5664