Check if TTY is present before invoking mesg

[tnation14]

Overview

When provisioning VMs, users see an error that says stdin: not a tty. This error is an instance of hashicorp/vagrant#1673, and stems from the fact that the bash profile for Ubuntu's root user runs mesg n without checkking to see if a TTY is present (see this comment on the issue for more detail). This PR Implements this fix, which adds a line to /root/.profile to check to see if a TTY is present before invoking mesg.

Fixes #66

Testing

Run vagrant provision, ensure that the stdin: not a tty error is not present.

[hectcastro]

I don't necessarily think that we need to merge this in. The issue summary signals that this isn't something that causes a problem, so I think we're OK with knowing that and living with the message. It is possible that Rob saw it at the end of the output and thought it halted further provisioning.

As another side-note, I have the following version of Vagrant on a Mac and was unable to reproduce:

athena Projects/geotrellis-site ‹master› » vagrant -v
Vagrant 1.9.5
athena Projects/geotrellis-site ‹master› » git rev-parse --short HEAD
f046bb4

[lossyrob]

Ok, apologies if this was a red herring - the only output from the provisioning step of the script is this line in a red line, so I assumed it failed (see below)

I'll continue assuming it didn't fail and raise any problems here or on the related issue.

[hectcastro]

Na, it is a legit issue that has sent me down rabbit holes in the past. In the end, I think the solution has potential to cause confusion, and the error itself is harmless. My point about not being able to reproduce it suggests that maybe things were patched up in the Vagrant internals.