Fix seg fault crash of quic_client with --disable-certificate-verification

When quic_client is executed with --disable-certificate-verification,
it crashes with segmentation fault due to SCT check in
ProofVerifierChromium. Instead, FakeProofVerifier is added in order to
pass VerifyProof when a certification verification is disabled.

BUG=

Review-Url: https://codereview.chromium.org/2441053002
Cr-Commit-Position: refs/heads/master@{#427003}
3 files changed