Fix linting

[coalest]

Fix for the lint warnings that occur when running the test suite:

$ bundle exec rspec
../rack-mini-profiler/lib/mini_profiler.rb:420: warning: assigned but unused variable - query_params
../rack-mini-profiler/lib/mini_profiler/actions.rb:133: warning: assigned but unused variable - status
Run options: include {:focus=>true}

All examples were filtered out; ignoring {:focus=>true}
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Finished in 7.32 seconds (files took 1.56 seconds to load)
292 examples, 0 failures

Coverage report generated for RSpec to ../rack-mini-profiler/coverage.
Line Coverage: 89.71% (1595 / 1778)

[nateberkopec]

Those are ruby warnings, not linters, but a good fix nonetheless 👍