ctdb/utils/etcd/ctdb_etcd_lock python => python3

[L.P.H. van Belle]

Hai, 

Latest samba build failed on ctdb. 
I dont know if its really needed but all python references are used with /usr/bin/env python3. 

Just to besure im not breaking something in ctdb here. 
Can someone confirm this? 

My fix.

--- a/ctdb/utils/etcd/ctdb_etcd_lock
+++ b/ctdb/utils/etcd/ctdb_etcd_lock
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python3


Greetz, 

Louis