vmware: default global pbm policy configuration

Adding support for a global pbm policy configuration for the vmdk
driver. Setting the 'pbm_default_policy' in cinder.conf will be
used as the default storage profile name to be used when creating
a volume without associated vmware:storage_profile extra spec.

Also renaming 'vmware-pbm-wsdl' to 'pbm-wsdl-location' to use
nova driver's naming convention.

Implements: blueprint vmdk-storage-policy-volume-type
Change-Id: I7fad167b7be6a479db88fb4d15d07f29afd023b0
vmware: PBM wsdl file configuration

Currently the PBM wsdl files have to be downloaded to the local file
system and needs to be configured in 'pbm_wsdl_location'. If it is
manually configured then PBM feature is enabled.

This patch does away with the manual configuration of
'pbm_wsdl_location'. PBM wsdl files are now shipped with the driver.
VC version is fetched from the backend server and the corresponding
wsdl file is used. If the backend is a VC version that is less than
5.5 then PBM feature is turned off.

Implements: blueprint vmdk-storage-policy-volume-type
Change-Id: I559006b532fa39aab6d54cb0b21d5f7afba62af3
Merge "vmware: default global pbm policy configuration"
Merge "vmware: PBM wsdl file configuration"