Automatic merge from submit-queue (batch tested with PRs 62378, 62734). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

 Add `snapfactor` storageclass parameter for GlusterFS provisioner.

This patch add a new parameter called `snapfactor` to glusterfs
    storageclass. This is an optional parameter and value should
    fall into the range of 1-100. When set the thin pool calculation
    respect this snapfactor and create a thinpool accordingly.
Signed-off-by: Humble Chirammal <hchiramm@redhat.com>




**What this PR does / why we need it**:

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #

**Special notes for your reviewer**:

**Release note**:

```release-note

```