In DHCP environment, Utils.getAddressHostName does not resolve hostname by ip address.

In DHCP environment, if SPARK_LOCAL_IP does not set, Spark Master webui shows spark url with IP address.
For example, my Spark Master shows spark master url with spark://150.24.194.45:7077.
In my case, I have to develop software in a variety of places.
So, I modify findLocalIpAddress to getLocalIpAddressAndHostName.
This code will show correct local hostname in DHCP environment.

Thanks.