beautify UserSettings error msg

fix up default dialog cancel button

src/components/structures/UserSettings.js

@@ -208,7 +208,7 @@ module.exports = React.createClass({
             var ErrorDialog = sdk.getComponent("dialogs.ErrorDialog");
             Modal.createDialog(ErrorDialog, {
                 title: "Can't load user settings",
-                description: error.toString()
+                description: "Server may be unavailable or overloaded",
             });
         });
     },

src/components/views/dialogs/BaseDialog.js

@@ -65,15 +65,14 @@ export default React.createClass({
     },
 
     render: function() {
+        const TintableSvg = sdk.getComponent("elements.TintableSvg");
+                
         return (
             <div onKeyDown={this._onKeyDown} className={this.props.className}>
                 <AccessibleButton onClick={this._onCancelClick}
                     className="mx_Dialog_cancelButton"
                 >
-                    <img
-                        src="img/cancel.svg" width="18" height="18"
-                        alt="Cancel" title="Cancel"
-                    />
+                    <TintableSvg src="img/icons-close-button.svg" width="35" height="35" />
                 </AccessibleButton>
                 <div className='mx_Dialog_title'>
                     { this.props.title }