fix styling of clearButton when its not there

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

src/components/structures/TagPanel.js

@@ -127,7 +127,9 @@ const TagPanel = React.createClass({
         }
 
         return <div className="mx_TagPanel">
-            { clearButton }
+            <div className="mx_TagPanel_clearButton_container">
+                { clearButton }
+            </div>
             <div className="mx_TagPanel_divider" />
             <GeminiScrollbarWrapper
                 className="mx_TagPanel_scroller"