Fix some lintian errors

Fix lintian errors related to maintainer, postinst script and
permissions.

Change-Id: I6924ff92ff5453fa7e562a6188c2c91cea87df68

src/DEBIAN_postinst.in

@@ -1,4 +1,4 @@
-#/bin/bash
+#!/bin/bash
 
 # This will return 0 if an id is created and non-zero if
 # it already exists