openrc stopped working on zsh

[YAMAMOTO Takashi]

after the recent GIT_DEPTH change, openrc stopped working on zsh.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/132160

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/132160
Committed: https://git.openstack.org/cgit/openstack-dev/devstack/commit/?id=292b2a7ee61f9b034230e8c99d2e5c7154dcf79b
Submitter: Jenkins
Branch: master

commit 292b2a7ee61f9b034230e8c99d2e5c7154dcf79b
Author: YAMAMOTO Takashi <email address hidden>
Date: Fri Oct 31 13:48:58 2014 +0900

    Workaround openrc failure on zsh

    The recent GIT_DEPTH change introduced a [[ ]] construct
    which doesn't work for zsh 5.0.2. Workaround it by tweaking the test.

    The following is a demonstration to show how zsh behaves:

        % if [[ "" ]];then echo hoge;fi
        zsh: parse error near `]]'
        % if [[ "x" ]];then echo hoge;fi
        zsh: parse error near `]]'
        % if [[ -n "" ]];then echo hoge;fi
        % if [[ -n "x" ]];then echo hoge;fi
        hoge
        %

    Closes-Bug: #1387943
    Change-Id: Ia88de876dacb3664a7c3d8f5a035e8e50fddb678