Database: Add $allow_bail argument to wpdb::check_connection() to match the connect method.

props DrProtocols, pento.
fixes #27240.

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Twenty Thirteen and Fourteen: style to support the new HTML5 line-break-less galleries. Props obenland, see #27637.
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git-svn-id: http://core.svn.wordpress.org/trunk@27756 1a063a9b-81f0-0310-95a4-ce76da25c4cd