Proxy logs violation for request with multiple or optional security schemes

[richjyoung]

This looks like the same issue as #80, except this affects the proxy mode rather than the mock server.

Given the following securitySchemes:

securitySchemes:
  Session:
    type: apiKey
    in: cookie
    name: session
  APIKey:
    type: apiKey
    in: header
    name: "X-API-Key"

In both of the following cases a request with the given security section will log a violation of "API Key X-API-Key not found in header":

# Optional security
security:
  - {}
  - APIKey: []

# Either Cookie or API Key security required
security:
  - Session: []
  - APIKey: []

No violation is logged for the cookie authentication which is present in the request in both cases.