fly: Add test for bash completion
fly: Add test for bash completion

When using fly with other application level headers
(--print-table-headers or --verbose) bash completion suddenly breaks.
This test ensures this doesn't happen in the future.

example:
Before, running `fly --verbose -t ci gp -p conc` would silently fail. If
you excluded the --verbose flag bash completion would suddenly start
working. Now bash completion always works, regardless of the other flags
being passed into the flag parser.

Signed-off-by: Taylor Silva <33b075afcd0610c62dcb82fe76b4c1adc69221da@pivotal.io>

concourse/concourse,concourse/concourse,concourse/concourse,concourse/concourse,concourse/concourse