keyring search regression in master

[NIIBE Yutaka]

Hello,

I found a problem in master.  2.1.9 works fine.

To reproduce:

# Setup
$ mkdir /tmp/gpghome; chmod og-rwx /tmp/gpghome
$ echo "default-key 00B45EBD4CA7BABE" >/tmp/gpghome/gpg.conf

# Get the public key
$ gpg --homedir=/tmp/gpghome --keyserver pool.sks-keyservers.net --recv-key 00b45ebd4ca7babe

# List with LONG-ID doesn't work
$ gpg2 --homedir=/tmp/gpghome --list-key 79A79093084239CF
gpg: error reading key: No public key

# ... while list with SHORT-ID works
$ gpg2 --homedir=/tmp/gpghome --list-key 084239CF
pub   rsa2048/4CA7BABE 2010-10-15
uid         [ unknown] NIIBE Yutaka <gniibe at fsij.org>
uid         [ unknown] NIIBE Yutaka <gniibe at debian.org>
sub   secp256k1/975B9053 2014-01-16
sub   rsa2048/084239CF 2010-10-15
sub   rsa2048/5BB065DC 2010-10-22

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