qa: remove osd pool create erasure tests

qa: remove osd pool create erasure tests

Creating an erasure pool will crash the OSD because OSD::_make_pg
asserts if the type is not replicated. The tests related to erasure
coded pool creation are removed from qa/workunits/cephtool/test.sh.

The osd-create-pool.sh unit test covers the cases removed from test.sh
more extensively. The intent is to check the interactions with the MON
only, therefore it does not run an OSD and the absence of erasure code
placement group backend implementation is not an issue.

Signed-off-by: Loic Dachary <loic@dachary.org>