fixes https://github.com/openebs/openebs/issues/934
fixes https://github.com/openebs/openebs/issues/934

1. Why is this change necessary ?

It is seen that volume capacity is always taken from
StorageClass parameters. However, the capacity property
set in PVC should always prevail over any other value.

2. How does this change address the issue ?

- changes the priority order & sets highest priority to
PVC

3. How to verify this change ?

- create volume by setting volume capacity in PVC & StorageClass

4. What side effects does this change have ?

- None

openebs/maya,AmitKumarDas/maya,prateekpandey14/maya,prateekpandey14/maya,AmitKumarDas/maya,gkGaneshR/maya,openebs/maya,openebs/maya,gkGaneshR/maya