converts aa-status checks to rspec-friendly matchers
converts aa-status checks to rspec-friendly matchers

Using `sed -ne /<START_PATTERN/,/<STOP_PATTERN>/ p` was too clever by
half. The built-in rspec `contains` matcher supports chaining with
.from and .to, which accomplishing the same as the ugly one-liner.

mark-in/securedrop-prov-upstream,mark-in/securedrop-prov-upstream,mark-in/securedrop-prov-upstream,mark-in/securedrop-prov-upstream