Change permissions on Serial TTY

[bensallen]

Hkmgr starts the hyperkit VM with the autopty option to symlink the serial TTY into the run dir, eg.

$ ls -la .run/vm/ros-vm1/tty
lrwxr-xr-x  1 root  staff  12 Nov 18 22:49 .run/vm/ros-vm1/tty -> /dev/ttys001

Hkmgr should try to chown this tty to the UID:GID of the running user, so the user doesn't need to elevate permissions to access to console, eg. sudo screen /dev/ttys001.