fix(img): img link on login

public/app/partials/login.html

@@ -3,7 +3,7 @@
 	<div class="login-box">
 
 		<div class="login-box-logo">
-			<img class="logo-icon" src="img/grafana_icon.svg"></img><br>
+			<img class="logo-icon" src="public/img/grafana_icon.svg"></img><br>
 			<i class="icon-gf icon-gf-grafana_wordmark"></i>
 		</div>