Scripts to use pyflakes to check python syntax.

pyflakes runs a basic syntax checker against python code.
The added check-syntax.sh script and Makefile run pyflakes
on the python code within the teuthology directory reporting
any syntax errors that are found.

Signed-off-by: Sam Lang <sam.lang@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Fixes for syntax errors found by pyflakes.

This patch includes minor fixes to the teuthology
python code for syntax errors found by running
check-syntax.sh (which runs pyflakes on each file).

Signed-off-by: Sam Lang <sam.lang@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>