Support Volume Expansion

[ekristen]

Since local-path-provisioner does not enforce capacity limitations, then I see no reason to throw errors in the event that someone changes the spec.capacity settings.

The following PR implements a partial fix that does away with the error messages. The remaining fix would be to simply update the PVC status to match the spec in a no-op function since it doesn't actually enforce or have to provision space.

Again since there is zero enforcement I see no reason to not simply set the setting that allows for volume expansion.

The error being only dynamically provisioned pvc can be resized and the storageclass that provisions the pvc must support resize

PR - https://github.com/rancher/local-path-provisioner/pull/189

Other issues

• https://github.com/rancher/local-path-provisioner/issues/107
• https://github.com/rancher/local-path-provisioner/issues/18

[ekristen]

Is there any reason to not do this? If the provisioner isn't actually enforcing or check data sizes, why not allow the size to be changed so it doesn't throw an error?