Improve the console output for extract-keys and speed up import.

Improve the console output for extract-keys and speed up import.

The listing of imported keys to the console must have stopped working
on 2014-12-31 due to a fix for bug #3698, commit
bbc5acb6de0ca56d7e8366402d68a1a919ca9b23 which was needed due to a
not fully working stub code introduced in 2008 with commit
a4b3a60dd63bc7af7927025b2d1344530ca89aa9.

The latter commit also introduced a bug in the import code which
listed all keys in the keyring to a temporary file and copied that one
to stdout.  The former commit avoided the output to stdout.

The fix here is to use pgp_gpgme_extract_keys only for extracting
information about the key and don't re-use the same code for importing
keys.  We now import the keys directly in pgp_gpgme_invoke_import and
we print the fingerprint and status flags for all imported keys.  That
information available from GPGME for ages (0.3.1 from 2003).
The user id is unfortunately not printed; that would require a lookup
of the newly imported key.  Can be done with another patch.