Fix more style warnings

browser/components/ModalEscButton.js

@@ -8,7 +8,7 @@ const ModalEscButton = ({
 }) => (
   <button styleName='escButton' onClick={handleEscButtonClick}>
     <div styleName='esc-mark'>×</div>
-    <div styleName='esc-text'>esc</div>
+    <div>esc</div>
   </button>
 )
 

browser/components/SnippetTab.js

@@ -114,7 +114,7 @@ class SnippetTab extends React.Component {
           >
             {snippet.name.trim().length > 0
               ? snippet.name
-              : <span styleName='button-unnamed'>
+              : <span>
                 {i18n.__('Unnamed')}
               </span>
             }