(hoepfully) fixed ref-counting in vacuum(), SQLvacuum(), SQLcluster1(), SQLcluster2(), compression()
(hoepfully) fixed ref-counting in vacuum(), SQLvacuum(), SQLcluster1(), SQLcluster2(), compression()

at least the vacuum test now works without ref-counting exception


Details:

- Whenever we release a BAT of which we have a logical reference,
  make sure we release that logical reference (BBPdecref(..., TRUE);)
  rather than a physical reference (BBPreleaseref(...);).

- Whenever we release a BAT of which we have a physical reference,
  make sure we release that physical reference (BBPreleaseref(...);)
  rather than a logical reference (BBPdecref(..., TRUE);).

- Make sure we free logical references to BATs in struct sql_delta
  before we clear / overwrite them.

- Avoid releasing more refenrences than we hold.

zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb