udroid ro.product.name: Set to thostname

For Microdroid, initialize ro.product.name with hostname. This is useful
for Microdroid like systems, where hostname is different for different
VMs & should be part of build fingerprint.

Test: (With topic) Start VM & getprop ro.product.name
Bug: 435640784
Flag: Exempt Minor change
Change-Id: I67c9c6bcde48192ae164bdd6855c4e1b04a32233