fix incorrect variable reference causing all RedHat os_family tests to fail

Author: Joe Bowman

bind/files/redhat/named.conf

@@ -8,7 +8,7 @@
 //
 
 options {
-        directory       "{{ named_directory }}";
+        directory       "{{ map.get('named_directory') }}";
         dump-file       "/var/named/data/cache_dump.db";
         statistics-file "/var/named/data/named_stats.txt";
         memstatistics-file "/var/named/data/named_mem_stats.txt";