due to default replica count, on single node the csi deployment is not created with replica 1

[Madhu-1]

In Rook testing with v1.0.3, the changes from this PR resulted in the following unexpected behavior:

• The default value in the CRD is 2. The absence of the setting in the CR is interpreted as 2, and we never hit the code path that checks for nodes. The CR setting is always applied, and never defaults to 1 for a single node.
• The replicas value set in OperatorConfig CR does not apply to the driver. If setting replicas: 1 in the OperatorConfig, two replicas are still started for each driver. The only way to set replicas: 1 currently is on each individual driver CR. The OperatorConfig replicas does not seem to apply.

Originally posted by @travisn in #517 (comment)