Add an option to change the device hostname (2/2)

This adds an option to modify the device hostname used
in ip resolution. This is useful when connecting to the
android device in a dynamic dhcp environment.

PS2: move preference above the debugging section

Change-Id: Ibc145b74036617248d4f33c6866cc9c8a8cc8974
Signed-off-by: Rohan Mathur <rohanmathur34@gmail.com>