Fix display of site registration fieldset in IE

Signed-off-by: Richard Mansfield <richardm@catalyst.net.nz>

htdocs/theme/raw/static/style/style.css

@@ -327,7 +327,7 @@ fieldset.collapsed {
 }
 fieldset.collapsed table {
     position: absolute;
-    visibility: hidden;
+    display: none;
 	padding: 0;
 	border: 0;
 	margin: 0;