gnome-keyring Review: Key fingerprints

[Stef Walter <stefw collabora co uk>]

Displaying key fingerprints in the key widget (analogous to the
certificate widget) is a bit complicated. There's real consistent way
(between packages) to generate a fingerprint for a key.

This patch implements the semi-standard hash-of-subjectPublicKeyInfo in
order to get a consistent fingerprint. This has the benefit of matching
the key-fingerprint on a certificate and the corresponding key.

Here's the implementation of the fingerprinting, and the display in the
widget. Two related bugs:

https://bugzilla.gnome.org/show_bug.cgi?id=646901

https://bugzilla.gnome.org/show_bug.cgi?id=646905

If anyone has time to look over the code, that's greatly appreciated.

Cheers,

Stef