create share from snapshot failed when using HDFS driver

[li,chen]

When working with HDFS driver, create a share from snapshot failed with error:

2015-09-11 11:20:00.697 DEBUG oslo_concurrency.processutils [req-2edc3d89-b127-46c8-a490-c73cf08e5fab dab3fa1bc89e44d98e44513f090a747b c15f038e0e8849bc911ba57dd3c1f875] u'hdfs dfs -cp -r /share-c15ff4a7-de9c-48ba-98f8-1556c7b93094/.snapshot/share-snapshot-7a1836e0-83ff-4f14-838e-229b48c74e09 /share-6973de1c-238f-4a26-bf59-31c6e42396ad' failed. Not Retrying. from (pid=6965) execute /usr/local/lib/python2.7/dist-packages/oslo_concurrency/processutils.py:308
2015-09-11 11:20:00.698 ERROR manila.share.drivers.hdfs.hdfs_native [req-2edc3d89-b127-46c8-a490-c73cf08e5fab dab3fa1bc89e44d98e44513f090a747b c15f038e0e8849bc911ba57dd3c1f875] Failed to create share share-6973de1c-238f-4a26-bf59-31c6e42396ad from snapshot share-snapshot-7a1836e0-83ff-4f14-838e-229b48c74e09. Error: Unexpected error while running command.
Command: hdfs dfs -cp -r /share-c15ff4a7-de9c-48ba-98f8-1556c7b93094/.snapshot/share-snapshot-7a1836e0-83ff-4f14-838e-229b48c74e09 /share-6973de1c-238f-4a26-bf59-31c6e42396ad
Exit code: 255
Stdout: u''
Stderr: u'-cp: Illegal option -r\nUsage: hadoop fs [generic options] -cp [-f] [-p | -p[topax]] <src> ... <dst>\n'.
2015-09-11 11:20:00.699 ERROR manila.share.manager [req-2edc3d89-b127-46c8-a490-c73cf08e5fab dab3fa1bc89e44d98e44513f090a747b c15f038e0e8849bc911ba57dd3c1f875] Share instance 6973de1c-238f-4a26-bf59-31c6e42396ad failed on creation.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/222479

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/222479
Committed: https://git.openstack.org/cgit/openstack/manila/commit/?id=d86fb3834022cb2c5b0ef665a59ee9c886a8774e
Submitter: Jenkins
Branch: master

commit d86fb3834022cb2c5b0ef665a59ee9c886a8774e
Author: Li, Chen <email address hidden>
Date: Fri Sep 11 14:09:51 2015 +0800

    Check the snapshot directory before copy it

    1. HDFS do not support "-r" option when copy data
    2. only un-empty directories can be copied

    Change-Id: I525556842191be6ca273293457327d3d3480832d
    Closes-Bug: 1494568