use /bin/sh instead of /bin/bash, since the latter may not be included in
some images such as minimal

Upstream-Status: Inappropriate [configuration]

Signed-off-by: Scott Garman <scott.a.garman@intel.com>

--- base-passwd/passwd.master~nobash
+++ base-passwd/passwd.master
@@ -1,4 +1,4 @@
-root:*:0:0:root:/root:/bin/bash
+root:*:0:0:root:/root:/bin/sh
 daemon:*:1:1:daemon:/usr/sbin:/bin/sh
 bin:*:2:2:bin:/bin:/bin/sh
 sys:*:3:3:sys:/dev:/bin/sh