Description of problem:
the return value of ping for ipv4 and ipv6 isn't the same

Version-Release number of selected component (if applicable):
ping utility, iputils-s20160308
3.10.0-481.el7.x86_64

How reproducible:
Always

Steps to Reproduce:
1. add unreachable route for ipv4
2. ping unreachable dst
3. add unreachable route for ipv6
4. ping6 unreachable dst

Actual results:
return value in 2 is 2
return value in 4 is 1

Expected results:
the return value should be the same 2

Additional info:

[root@ibm-x3250m5-01 route_type]# uname -a
Linux ibm-x3250m5-01.rhts.eng.pek2.redhat.com 3.10.0-481.el7.x86_64 #1 SMP Wed Jul 27 18:24:27 EDT 2016 x86_64 x86_64 x86_64 GNU/Linux

[root@ibm-x3250m5-01 route_type]# ping6 -V
ping utility, iputils-s20160308

[root@ibm-x3250m5-01 route_type]# ip route add unreachable 2000::/64

[root@ibm-x3250m5-01 route_type]# ping6 2000::1 -c 1
PING 2000::1(2000::1) 56 data bytes
ping: sendmsg: No route to host

--- 2000::1 ping statistics ---
1 packets transmitted, 0 received, 100% packet loss, time 0ms

[root@ibm-x3250m5-01 route_type]# echo $?
1
<======1 here

[root@ibm-x3250m5-01 route_type]# ping 192.168.0.1 -c 1
connect: No route to host
[root@ibm-x3250m5-01 route_type]# echo $?
2
<========2 here

When use ping on rhel7.2GA whose version is iputils-s20121221,the return value is 2:

[root@dhcp-13-64 ~]# uname -a
Linux dhcp-13-64.nay.redhat.com 3.10.0-481.el7.x86_64 #1 SMP Wed Jul 27 18:24:27 EDT 2016 x86_64 x86_64 x86_64 GNU/Linux

[root@dhcp-13-64 ~]# ping -V
ping utility, iputils-s20121221

[root@dhcp-13-64 ~]# ping6 2000::1 -c 1
connect: No route to host
[root@dhcp-13-64 ~]# echo $?
2