samples/pktgen: Use bash as interpreter

These scripts use the non-POSIX 'function' and 'local' keywords so
they won't work with every /bin/sh.  We could drop 'function' as it is
a no-op, but 'local' makes for cleaner scripts.  Require use of bash.
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

samples/pktgen/pktgen.conf-1-1

-#! /bin/sh
+#!/bin/bash
 
 #modprobe pktgen
 

samples/pktgen/pktgen.conf-1-1-flows

-#! /bin/sh
+#!/bin/bash
 
 #modprobe pktgen
 

samples/pktgen/pktgen.conf-1-1-ip6

-#! /bin/sh
+#!/bin/bash
 
 #modprobe pktgen
 

samples/pktgen/pktgen.conf-1-1-ip6-rdos

-#! /bin/sh
+#!/bin/bash
 
 #modprobe pktgen
 

samples/pktgen/pktgen.conf-1-1-rdos

-#! /bin/sh
+#!/bin/bash
 
 #modprobe pktgen
 

samples/pktgen/pktgen.conf-1-2

-#! /bin/sh
+#!/bin/bash
 
 #modprobe pktgen
 

samples/pktgen/pktgen.conf-2-1

-#! /bin/sh
+#!/bin/bash
 
 #modprobe pktgen
 

samples/pktgen/pktgen.conf-2-2

-#! /bin/sh
+#!/bin/bash
 
 #modprobe pktgen