Set config file to db sync and other manage operation

Currently, the db sync operation does not specify the config dir or
config file.
If there is a config file in the home path, it will use this one,
but not the right one devstack write.

Set config file to these operations.

Change-Id: Id1fbc3d85280c19596f5ebd301c46bcf018fa2f6
Closes-Bug: #1578098
diff --git a/lib/heat b/lib/heat
index 4326321..730adad 100644
--- a/lib/heat
+++ b/lib/heat
@@ -241,7 +241,7 @@
     # (re)create heat database
     recreate_database heat
 
-    $HEAT_BIN_DIR/heat-manage db_sync
+    $HEAT_BIN_DIR/heat-manage --config-file $HEAT_CONF db_sync
     create_heat_cache_dir
 }