add shebang lines to all lib files

With gerrit 2.8, and the new change screen, this will trigger syntax
highlighting in gerrit. Thus making reviewing code a lot nicer.

Change-Id: Id238748417ffab53e02d59413dba66f61e724383
diff --git a/lib/neutron_thirdparty/midonet b/lib/neutron_thirdparty/midonet
index 099a66e..2c82d48 100644
--- a/lib/neutron_thirdparty/midonet
+++ b/lib/neutron_thirdparty/midonet
@@ -1,3 +1,5 @@
+#!/bin/bash
+#
 # MidoNet
 # -------