login share server maybe fail with private key during creating a share

[wang yong]

When using the GenericShareDriver and creating a share, the create routine maybe failed after the new share server created, and during to login it with private key to initialize the share server, especially on a slow test environment node.

The code only check the server availability with connect to the port, however, even when the port is reachable, the login maybe failed, we should check the login too.

share backend config in /etc/manila/manila.conf:

[generic1]
admin_subnet_id = d904feb9-470a-45a1-97c8-d6adbf653211
admin_network_id = 41c38256-dcfa-4ed8-b8f6-dba210ef91be
driver_handles_share_servers = True
service_instance_user = manila
service_image_name = manila-service-image-master
path_to_private_key = /opt/stack/.ssh/id_rsa
path_to_public_key = /opt/stack/.ssh/id_rsa.pub
share_backend_name = GENERIC1
share_driver = manila.share.drivers.generic.GenericShareDriver

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/542739

[Victoria Martinez de la Cruz (vkmc)]

Checked during Manila bug squash, seems that the proposed fix is valid, would need to be rebased and reviewers comments addressed. Bug needs to be reproduced with the condition that reporter indicated (slow environment). If anybody is interested on picking this one up, you are encouraged to do that!