VMware: remove unused parameter (mountpoint)

A mountpoint parameter was passed to the volume attach and detach
methods. This parameter is not used. This patch cleans that up.
In addition it also cleans log messages where this parameter was used.

TrivialFix

Change-Id: I2eafea22c58553ac58fcccf6d199db6f8b595fb2
Merge "VMware: remove unused parameter (mountpoint)"