Get rid of old error codes.

* g10/gpg.h: Remove error codes compatibility #DEFINEs
* g10/armor.c: Rename old error codes to the new ones
* g10/compress.c: Ditto
* g10/delkey.c: Ditto
* g10/exec.c: Ditto
* g10/getkey.c: Ditto
* g10/gpgv.c: Ditto
* g10/import.c: Ditto
* g10/keydb.c: Ditto
* g10/keyedit.c: Ditto
* g10/keygen.c: Ditto
* g10/keyring.c: Ditto
* g10/keyserver.c: Ditto
* g10/mainproc.c: Ditto
* g10/misc.c: Ditto
* g10/parse-packet.c: Ditto
* g10/pkclist.c: Ditto
* g10/plaintext.c: Ditto
* g10/pubkey-enc.c: Ditto
* g10/revoke.c: Ditto
* g10/seckey-cert.c: Ditto
* g10/sig-check.c: Ditto
* g10/sign.c: Ditto
* g10/tdbio.c: Ditto
* g10/trustdb.c: Ditto
* g10/verify.c: Ditto
* sm/keydb.c: Ditto