test case added for transport/tty_serial.py
test case added for transport/tty_serial.py

pklimai/py-junos-eznc,pklimai/py-junos-eznc,Juniper/py-junos-eznc,pklimai/py-junos-eznc,spidercensus/py-junos-eznc,spidercensus/py-junos-eznc,Juniper/py-junos-eznc,Juniper/py-junos-eznc,spidercensus/py-junos-eznc