Remove the broken "User Dashboard" link.

Due to the lack of a </a>, this makes the entire header render badly.
Accordingly it's safe to assume noone is using it, so remove it.
With the new console template support, we'll need to something a bit
more nuanced later.

Change-Id: I3424bed6aea18cbd4c63ad48f98808098dadc3ad

web/templates/_base.html

@@ -17,8 +17,6 @@
         <div class="container-fluid">
           <a class="brand" href="/">Prometheus</a>
           <ul class="nav">
-            <li>{{ define "user_dashboard_link" }}{{ end }}
-                {{ template "user_dashboard_link" .}}</li>
             <li><a href="/alerts">Alerts</a></li>
             <li><a href="/graph">Graph</a></li>
             <li><a href="/">Status</a></li>

web/web.go

@@ -141,11 +141,6 @@ func getTemplate(name string) (t *template.Template, err error) {
 		return
 	}
 
-	if *userAssetsPath != "" {
-		// replace "user_dashboard_link" template
-		t.Parse(`{{define "user_dashboard_link"}}<a href="/user">User Dashboard{{end}}`)
-	}
-
 	return
 }