Fix a typo and some small Trusty fixes.

On newer ubuntu's, ruby gems come for free with the 'ruby' package,
so no need for a separate rubygems package (in fact, it doesn't
work).  On the other hand, pip install doesn't work because the curses
library is missing, so I install that.

I also fixed a typo.  No idea how that got in there.

I also also changed the Makefile to make sure that setup-<os>.sh runs
*before* setup.sh.  Before, they would run in parallel if you did
'make -j2'.

Auditors: alpert

Test Plan:
Ran 'make' on my 14.04 machine, with success.