src: Fix dummy engine versions.

Previously, 'gpgme_engine_check_version' failed for these protocols
because the version parser failed to parse the dummy versions.

• src/engine-assuan.c (llass_get_version): Use a version triple that

the parser can understand.
(llass_get_req_version): Likewise.

• src/engine-spawn.c (engspawn_get_version): Likewise.

(engspawn_get_req_version): Likewise.

• src/engine-uiserver.c (uiserver_get_version): Likewise.

(uiserver_get_req_version): Likewise.

• Signed-off-by: Justus Winter <justus@g10code.com>