Support error type

Since version 2.4.1, responses for errors have extra information following what was described in Box protocol – responses for errors. This is a “compatible” enhancement, because clients that expect old-style server responses should ignore map components that they do not recognize. Notice, however, that there has been a renaming of a constant: formerly IPROTO_ERROR in ./box/iproto_constants.h was 0x31, now IPROTO_ERROR is 0x52 and IPROTO_ERROR_24 is 0x31.

MP_ERROR type is 3.

See doc for more details.

It seems that to fully support MP_ERROR, #206 is a prerequisite:
https://github.com/tarantool/tarantool/blob/2e9cbec3091e7c5d6ca1d7dad4305333e70f5876/src/box/iproto_features.h#L31-L42