Fixed logout link

src/app/partials/sidemenu.html

@@ -27,7 +27,7 @@
 				<span class="gravatar-email small">{{grafana.user.login}}</span>
 			</a>
 			<ul class="dropdown-menu">
-				<li><a href="{{appSubUrl}}/login?logout">Logout</a></li>
+				<li><a href="{{appSubUrl}}/logout">Logout</a></li>
 			</ul>
 		</li>
 	</ul>