Tighten expectation on ENV keys
Tighten expectation on ENV keys

Bundler.with_clean_env will only remove keys that begin with
'BUNDLE_', but this test was matching on 'BUNDLE', which would fail if
any env variables (e.g. 'BUNDLER_xxxxx') were still present. This
problem only occurs on newer (>= 1.13.2) Bundlers.

Signed-off-by: Tom Viehman <ef9e7682e71c138189ac51545830b782ff2b8b7d@pivotal.io>

barthy1/bosh,barthy1/bosh,barthy1/bosh,barthy1/bosh