Remove non-working RSS <link> tag

{{rsslink}} has been undefined since commit 63d1d956fbc (Fix RSS link).

I originally tried this change:

```
-    <link rel="alternate" type="application/rss+xml"  href="{{rsslink}}" title="Latest Crash Reports">
+    <link rel="alternate" type="application/rss+xml"  href="/acra-{{acralyzer.app}}/_design/acra-storage/_list/rss/recent-items?descending=true" title="Latest Crash Reports">
```

The substitution looked fine in the Firefox Inspector, but Firefox apparently parses the RSS URL too early during the page load process; clicking "Subscribe to this page" did nothing, and Tamper Data showed a GET request to `/acra-%7B%7Bacralyzer.app%7D%7D...`

Manually replacing {{acralyzer.app}} with my app's literal name made "Subscribe to this page" work again.

This page corroborates my claim that Firefox is picky about editing the `<link>` href from Javascript, and suggests a few other alternatives:

http://ask.metafilter.com/54377/Firefox-and-Javascript-issue