[DevStack]: unstack should remove etcd directory

[Dongcan Ye]

When we using devstack install kuryr-libnetwork, there may be some exception in install etcd data store, like network timeout, IO error.

Then we need to run ./unstack cancel previous installation. But /etcd dir had not removed, so we may met error like:

2016-08-09 02:51:43.900 | ++functions-common:is_service_enabled:2078 return 1
2016-08-09 02:51:43.904 | +functions-common:run_phase:1895 [[ stack == \s\o\u\r\c\e ]]
2016-08-09 02:51:43.908 | +functions-common:run_phase:1898 [[ stack == \o\v\e\r\r\i\d\e\_\d\e\f\a\u\l\t\s ]]
2016-08-09 02:51:43.913 | +functions-common:run_phase:1901 run_plugins stack install
2016-08-09 02:51:43.918 | +functions-common:run_plugins:1860 local mode=stack
2016-08-09 02:51:43.922 | +functions-common:run_plugins:1861 local phase=install
2016-08-09 02:51:43.926 | +functions-common:run_plugins:1863 local plugins=,kuryr-libnetwork
2016-08-09 02:51:43.930 | +functions-common:run_plugins:1864 local plugin
2016-08-09 02:51:43.935 | +functions-common:run_plugins:1865 for plugin in '${plugins//,/ }'
2016-08-09 02:51:43.939 | +functions-common:run_plugins:1866 local dir=/opt/stack/kuryr-libnetwork
2016-08-09 02:51:43.944 | +functions-common:run_plugins:1867 [[ -f /opt/stack/kuryr-libnetwork/devstack/plugin.sh ]]
2016-08-09 02:51:43.949 | +functions-common:run_plugins:1868 source /opt/stack/kuryr-libnetwork/devstack/plugin.sh stack install
2016-08-09 02:51:43.971 | Installing etcd server
2016-08-09 02:51:43.972 | mkdir: cannot create directory '/opt/stack/etcd': File exists
2016-08-09 02:51:43.973 | Error on exit

I think we should run rm command clean the etcd directory in unstack script.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/352692

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/352692
Committed: https://git.openstack.org/cgit/openstack/kuryr-libnetwork/commit/?id=eb3f8af8127bbaf2ec868f98d6d97cb6fe67a4a3
Submitter: Jenkins
Branch: master

commit eb3f8af8127bbaf2ec868f98d6d97cb6fe67a4a3
Author: Dongcan Ye <email address hidden>
Date: Tue Aug 9 11:30:11 2016 +0800

    Remove etcd directory in uninstall

    When we install kuryr-libnetwork, there may be some exception
    in install etcd data store, like network timeout, IO error.
    Then we may met file exists error reinstall.

    We can clean up the etcd directory in unstack script.

    Change-Id: I77dd701dcda7866b2d09dd9b334a64df21f5762c
    Closes-Bug: #1611187