Set user-scalable=no in viewport meta tag (#23883).

Patch by Felix Gliesche.

git-svn-id: http://svn.redmine.org/redmine/trunk@15849 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/views/layouts/base.html.erb

@@ -4,7 +4,7 @@
 <meta charset="utf-8" />
 <meta http-equiv="X-UA-Compatible" content="IE=edge"/>
 <title><%= html_title %></title>
-<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1">
+<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no">
 <meta name="description" content="<%= Redmine::Info.app_name %>" />
 <meta name="keywords" content="issue,bug,tracker" />
 <%= csrf_meta_tag %>