Conflict record stub has value of 5 bytes length: 1 byte for
storage.ExecTransaction prefix and 4 bytes for the block index LE. This
scheme was implemented in #3138, and this commit should be a part of
this PR.
Also, transaction.DummyVersion is removed since it's unused anymore.
Close#3426. The reason of `failed to locate application log: EOF` error
during genesis AER request is in the following: genesis executable was
overwritten by conflict record stub produced by transaction
0x289c235dcdab8be7426d05f0fbb5e86c619f81481ea136493fa95deee5dbb7cc (ref.
#3427). As a consequence, an attempt to decode transaction AER was
initited, but conflict record scheme was changed in #3138.
Signed-off-by: Anna Shaleva <shaleva.ann@nspcc.ru>