This commit adds the expected behaviour for all-defaulted records in
ROCK, provided the all-defaulted records are not the first of the
keyword. Similarly to, e.g. PVTW, all-defaulted records are treated as
copies of the immediately preceding record.
In other words, given
ROCK
-- REF. PRES COMPRESSIBILITY
280.000 5.6E-5 /
/
the second record is supposed to be a copy of the first.