QUIC: Update RSA keys to 2048-bit.

Chrome is going to start rejecting 1024-bit keys soon(ish) and so the
tests in Chrome will break with the QUIC testdata.

This also changes the ECC keys because the generation script uses a
pseudo-random sequence and the larger RSA keys cause the whole sequence
to shift.

Merge internal CL: 57071139

Fix a comment nit.

Merge internal CL: 57314431

I also added the quic_*.key files for future use. quic_test.example.com.key
and quic_test_ecc.example.com.key will be needed by a complete port of
crypto_server_test, proof_test, and quic_crypto_server_stream_test.

R=agl@chromium.org,rtenneti@chromium.org
BUG=none
TEST=none

Review URL: https://codereview.chromium.org/89063003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237513 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 237513