Update provider_client.go
Update provider_client.go

This change prevents errors "error waiting for instance to become ready" while deploying VMs in Openstack 
(when using Terraform, which requires gophercloud to talk to OpenStack)
timbyr/gophercloud,rackspace/gophercloud,jamiehannaford/gophercloud,jamiehannaford/gophercloud,rackspace/gophercloud,DSpeichert/gophercloud,DSpeichert/gophercloud,carolynvs/gophercloud,carolynvs/gophercloud,feiskyer/gophercloud,timbyr/gophercloud,feiskyer/gophercloud