By some reason, pvcreate method allocates two 64MiB metadata chunks by
default. We can/should make test how many vg/lv can be allocated using
default two 2MiB metadata chunks(this LVM defaults not our). But I
believe that it will be enough for any reasonable amount ov vg/lv.
We still can pass required metadata size, if we need to.
Update functional tests expected constants to match metadata size
update.
Change-Id: I0106fa35b7b21f16ce6a9a8794e6c88ba61ceeca