Incorrect dockvols location for VMs in nested folders in datastore

[pdhamdhere]

VM1: /vmfs/volumes/Storage1/Photon1.vmx
VM2: /vmfs/volumes/Storage1/test/abc/Photon2.vmx

Docker volumes created by VM1 are stored in;

 ls -al /vmfs/volumes/Storage1/dockvols/*flat.vmdk
-rw-------    1 root     root     214748364800 Jun  9 05:06 /vmfs/volumes/Storage1/dockvols/av2-flat.vmdk
-rw-------    1 root     root     104857600 Jun  9 16:22 /vmfs/volumes/Storage1/dockvols/v1-flat.vmdk

Docker volumes created by VM2 are stored in;

ls -al /vmfs/volumes/Storage1/test/abc/dockvols/*flat.vmdk
-rw-------    1 root     root     104857600 Jun  9 16:34 /vmfs/volumes/Storage1/test/abc/dockvols/pv1-flat.vmdk
-rw-------    1 root     root     104857600 Jun  9 16:44 /vmfs/volumes/Storage1/test/abc/dockvols/pv3-flat.vmdk

docker volume ls from VM1 reports volumes in /vmfs/volumes/Storage1/dockvols
docker volume ls from VM2 reports volumes in /vmfs/volumes/Storage1/test/abc/dockvols

We should always be creating dockvols in datastore\dockvols rather than in parent directory.

def getVolPath(vm_config_path);
# The volumes folder is created in the parent of the given VM's folder.
path = os.path.join(
     os.path.dirname(os.path.dirname(vm_config_path)), DOCK_VOLS_DIR) <------------

We can get VM datastore info from VirtualMachineConfigSummary.summary.config.vmPathName and use it to create "dockvols" directory.

This issue also has other side effects for e.g. volume creation and mounting works fine for Photon2.vmx but unmount/detach fails. with following error;

06/09/16 16:44:39 148482 [WARNING] *** Detach failed: disk=/vmfs/volumes/4bad174b-b67f5cfc-2fc6-0026b966a303/test/abc/dockvols/pv3.vmdk not found. VM=564d4469-ea2f-7e86-71ad-d1d43b627a9d

def findDeviceByPath(vmdk_path, vm):
...
        dvol_dir = os.path.dirname(vmdk_path)
        real_vol_dir = os.path.basename(os.path.realpath(dvol_dir)) <------
        virtual_disk = real_vol_dir + "/" + os.path.basename(vmdk_path)