Eli Schwartz authored Jun 08, 2020 and Allan McRae committed Jun 11, 2020

We pass this to gpg -u and this gpg option can accept a number of
different formats, not just the historical hexadecimal fingerprint we
assumed. We should not barf hard if a format is used which happens to
contain spaces.

This also fixes a validation bug. When we initially check if the desired
key is available, we don't quote spaces, so gpg goes ahead and treats
each space-separated string as a *different key* to search for,
returning partial matches, and returning success if at least one key is
found. But gpg --detach-sign -u will certainly not accept multiple keys!

Fixes FS#66949

Signed-off-by: Eli Schwartz <eschwartz@archlinux.org>
Signed-off-by: Allan McRae <allan@archlinux.org>