Improve logging of DNS record source from --hostsdir files.

Patch author Dominik Derigs <dl6er@dl6er.de> with subsequent bugfixes
and tweaks from Simon Kelley.

src/cache.c

@@ -1861,6 +1861,7 @@ void dump_cache(time_t now)
 char *record_source(unsigned int index)
 {
   struct hostsfile *ah;
+  struct dyndir *dd;
 
   if (index == SRC_CONFIG)
     return "config";
@@ -1872,9 +1873,11 @@ char *record_source(unsigned int index)
       return ah->fname;
 
 #ifdef HAVE_INOTIFY
-  for (ah = daemon->dynamic_dirs; ah; ah = ah->next)
-     if (ah->index == index)
-       return ah->fname;
+  /* Dynamic directories contain multiple files */
+  for (dd = daemon->dynamic_dirs; dd; dd = dd->next)
+    for (ah = dd->files; ah; ah = ah->next)
+      if (ah->index == index)
+	return ah->fname;
 #endif
 
   return "<unknown>";