Use the shell helper chown_r
Use the shell helper chown_r

Instead of using the shell execute command to
do the equivalent use the shell functions to
do the same. This allows us to detect when a user
or group does not exist as well as to indivually
report chown failures, instead of just silently
dropping said errors.

Change-Id: I73452de0034c44de1812bb2163cf8b0142910773

stackforge/anvil,stackforge/anvil,mc2014/anvil,mc2014/anvil