Fix map-file rewrite regex

Change-Id: If31aba8cfd466f9f5c9fc21441a454f53a4a4a0d
diff --git a/ironic/conductor.sls b/ironic/conductor.sls
index b8baa13..6f65a4c 100644
--- a/ironic/conductor.sls
+++ b/ironic/conductor.sls
@@ -61,8 +61,8 @@
   file.managed:
     - name: {{ conductor.tftp_root }}/map-file
     - contents: |
-        r ^([^/]) {{ conductor.tftp_root }}/\\1
-        r ^(/tftpboot/) {{ conductor.tftp_root }}/\2
+        r ^[^/] /\0
+        r ^({{ conductor.tftp_root }}) /\2
     - user: 'ironic'
     - group: 'ironic'
     - require: