Rename variable for consistency

// FREEBIE

background.html

@@ -190,7 +190,7 @@
           {{ /received_at }}
           {{ #errors }}
             <tr>
-              <td class='label'>{{ error-label }}</td>
+              <td class='label'>{{ errorLabel }}</td>
               <td> <span class='error-message'>{{message}}</span> </td>
             </tr>
           {{ /errors }}

js/views/message_detail_view.js

@@ -118,7 +118,7 @@
                 received    : i18n('received'),
                 resend      : i18n('resend'),
                 failedToSend: i18n('failedToSend'),
-                'error-label': i18n('error'),
+                errorLabel  : i18n('error'),
                 hasRetry    : hasRetry
             }));
             this.view.$el.prependTo(this.$('.message-container'));