Bump the ansible version to v2.0.0-0.7.rc2

The keystone_user is deprecated and the os_user module is added since
v2.0.0-0.4.beta2[0], which should be used for keystone user creation.

[0]
https://github.com/ansible/ansible-modules-core/commit/cdf7117f7eec002ff6fce5900d2706e8a1abc399

Closes-Bug: #1526589
Change-Id: Ibe791913af52df5eb22eecdfc0f0156e2d0019a4

docker/kolla-ansible/Dockerfile.j2

@@ -42,7 +42,7 @@ RUN curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py \
         shade \
         pyudev
 
-RUN git clone --depth 1 -b v2.0.0-0.2.alpha2 https://github.com/ansible/ansible.git \
+RUN git clone --depth 1 -b v2.0.0-0.7.rc2 https://github.com/ansible/ansible.git \
     && cd ansible \
     && git submodule update --init --recursive \
     && pip --no-cache-dir install .