gpg: Don't check for ambiguous keys.

* g10/gpg.c (struct result): Move from here...
* g10/keydb.h (struct pubkey): ... to here.  Update users.
* g10/gpg.c (check_user_ids): Move from here...
* g10/getkey.c (get_pubkeys): ... to here.  Update users.  Use
get_pubkey_byname to look up the keys (this also prunes invalid keys).
(pubkey_free): New function.
(pubkeys_free): New function.
* g10/gpg.c (main): Don't check for ambiguous key specifications.

--
Signed-off-by: Neal H. Walfield <neal@g10code.com>
Regression-due-to: e8c53fc

This change not only moves the checks for ambiguous key specifications
from gpg.c to getkey.c, it also disables the checks.  The old code was
too divorced from the actual key lookups and, as such, it reproduced
the logic.  Unfortunately, the reproduction was a poor one: despite
fixing some inconsistencies (e.g., 10cca02), it still didn't deal with
group expansion or the auto key lookup functionality.  Given the
amount of instability introduced by this change, we (Neal & Werner)
decided it is better to defer introducing this functionality until
2.3.

g10/keydb.h

@@ -485,6 +485,29 @@ int get_pubkey_fast ( PKT_public_key *pk, u32 *keyid );
    using merge_selfsigs.  */
 KBNODE get_pubkeyblock( u32 *keyid );
 
+/* A list used by get_pubkeys to gather all of the matches.  */
+struct pubkey
+{
+  struct pubkey *next;
+  /* The key to use (either the public key or the subkey).  */
+  PKT_public_key *pk;
+  kbnode_t keyblock;
+};
+
+/* Free a single key.  This does not remove key from any list!  */
+void pubkey_free (struct pubkey *key);
+
+/* Free a list of public keys.  */
+void pubkeys_free (struct pubkey *keys);
+
+/* Returns all keys that match the search specfication SEARCH_TERMS.
+   The returned keys should be freed using pubkeys_free.  */
+gpg_error_t
+get_pubkeys (ctrl_t ctrl,
+             char *search_terms, int use, int include_unusable, char *source,
+             int warn_possibly_ambiguous,
+             struct pubkey **keys);
+
 /* Find a public key identified by the name NAME.
 
    If name appears to be a valid valid RFC822 mailbox (i.e., email