Problem because of the race condition between chvt logind service and tty6 during installation of Red Hat Enterprise Linux 7.2 using kickstart?

Issue

• Why does python %pre script execution fail and halt installation of Red Hat Enterprise Linux 7.2 ?
• This works as expected with Red Hat Enterprise Linux 7.1 and 6.x whereas with Red Hat Enterprise Linux 7.2, it fails.
• The following example %pre script halts installation.

%pre --interpreter /bin/python
import os
import sys
import re
import os.path
import time
import socket
import commands
import urllib2, base64, sys, json, base64
from pprint import pprint

os.system('exec < /dev/tty6 > /dev/tty6')
os.system('chvt 6')
os.system('clear')

fd = os.open("/dev/tty6", os.O_RDWR)
os.dup2(fd, 0)
os.dup2(fd, 1)
os.dup2(fd, 2)
sys.stdin = os.fdopen(0, "r")
sys.stdout = os.fdopen(1, "w")
sys.stderr = os.fdopen(2, "w")

os.system('clear')
print ""
print " Testing Dracut"
print " ----------------------------------------"
print ""
print " Enter anything when prompted"
print ""
print " You should never see the command prompt"
print ""
print " ----------------------------------------"
print ""
print ""

fd = open("/tmp/rhel-dracut-test-out","w")
userinput = raw_input(" Enter something: ")
fd.write(userinput + '\n')

userinput = raw_input(" Enter more: ")
fd.write(userinput + '\n')

userinput = raw_input(" Enter last one: ")
fd.write(userinput + '\n')
fd.close

userinput = raw_input(" \nPress enter to display the file:")

fd = open("/tmp/rhel-dracut-test-out","r")
lines = fd.read()
print lines
fd.close()


userinput = raw_input(" \nPress enter to return to tty1")

os.system('chvt 1')
os.system('exec < /dev/tty1 > /dev/tty1')

%end