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/functions b/functions
index bb40a48..d33ad8c 100644
--- a/functions
+++ b/functions
@@ -1,3 +1,5 @@
+#!/bin/bash
+#
 # functions - DevStack-specific functions
 #
 # The following variables are assumed to be defined by certain functions: