cta/CTA#141 cta tape reclaim does not clean the occupancy field

Improved unit tests to test for the fact that reclaim should
reset the tape occupancy field.

The following unit now "succesfully" fails:

[ RUN      ] InMemory/cta_catalogue_CatalogueTest.reclaimTape_full_lastFSeq_1_no_tape_files/0
/home/smurray/CTA/catalogue/CatalogueTest.cpp:7029: Failure
Value of: tape.dataOnTapeInBytes
  Actual: 1
Expected: 0
[  FAILED  ] InMemory/cta_catalogue_CatalogueTest.reclaimTape_full_lastFSeq_1_no_tape_files/0, where GetParam() = 0x7fc58e93eab0 (7 ms)

The next step is to fix the bug in reclaim.