hgweb: add atom error template

templates/atom/error.tmpl

@@ -0,0 +1,17 b''
+{header}
+ <!-- Error -->
+ <id>{urlbase}{url}</id>
+ <link rel="self" href="{urlbase}{url}atom-log"/>
+ <link rel="alternate" href="{urlbase}{url}"/>
+ <title>Error</title>
+ <updated>1970-01-01T00:00:00+00:00</updated>
+ <entry>
+  <title>Error</title>
+  <id>http://www.selenic.com/mercurial/#error</id>
+  <author>
+    <name>mercurial</name>
+  </author>
+  <updated>1970-01-01T00:00:00+00:00</updated>
+  <content type="text">{error|escape}</content>
+ </entry>
+</feed>

templates/atom/map

@@ -8,3 +8,4 b' filelog = filelog.tmpl'
 filelogentry = filelogentry.tmpl
 tags = tags.tmpl
 tagentry = tagentry.tmpl
+error = error.tmpl