adb shell getprop failure when installing UTAH

[Javier Collado]

When using:
run_utah_phablet.py --skip-install --skip-network --ppa='ppa:utah/daily'

to install utah in a nexus4 device, I got errors in the `adb shell getprop`
command that `run_utah_phablet.py` uses internally. This is kind of strange
because when debugging the script and executing the command in a separate
window after the failure I didn't get any problem, so whatever happens
it does only when the command is executed the first time.

I'll add more information about this when I'm able to troubleshoot it properly.