[Qemu-block] [PATCH v4] crypto: Implement TLS Pre-Shared Keys (PSK).

[Richard W.M. Jones]

v4:

 - This addresses points raised by Eric and Dan's reviews.

The only thing I didn't change was using --object in qemu-options.hx,
since that would really be different from everything else in the file.
(However I did change -object -> --object in the header docs)

This version uses g_file_get_contents to read the whole PSK file into
memory, rather than using either fgets or getline.

Rich.