Make the helper Pod timeout configurable

[mgoltzsche]

...because depending on the helper Pod a different timeout may be needed.

My use case is cache-provisioner that requires the helper Pod to synchronize the volume contents with an image registry which may take more than the hardcoded timeout of 2 minutes.

[daicang]

Sometimes when load is high, helper pod takes more than 2min to create PV and would always timeout. Set timeout to 4min would solve this.

[Donatas-L]

I see that this was addressed in the #166, but it was never merged into the master. Is there any way to increase the timeout of helper pod by using master version of the provisioner? Or the only way to do this is to fork the project and edit the source code?

@daicang How you increased the timeout?