Mock Cpp2ConnContext

Summary:
Mock Cpp2ConnContext so the supplied cert to the constructor is available to
Cpp2::ConnContext->getTransport()->getPeerCertificate() call. This change is needed by other changes.

Reviewed By: edenzik

Differential Revision: D29791757

fbshipit-source-id: 42b8bb6024c880b038925a3f95b855de0488033b

folly/io/async/test/MockAsyncTransport.h

@@ -72,6 +72,7 @@ class MockAsyncTransport : public AsyncTransport {
   MOCK_METHOD1(
       setReplaySafetyCallback, void(AsyncTransport::ReplaySafetyCallback*));
   MOCK_CONST_METHOD0(getSecurityProtocol, std::string());
+  MOCK_CONST_METHOD0(getPeerCertificate, const AsyncTransportCertificate*());
 };
 
 class MockReplaySafetyCallback : public AsyncTransport::ReplaySafetyCallback {