ansible playbook bugfix

ansible playbook bugfix

According the qtip ci results, make these bugfixs.
1. skipping: no hosts matched
   This used to work in Ansible 1.9.x with 127.0.0.1;But does not work in Asible 2.x
   solved: add 127.0.0.1 as localhost in ./data/hosts
2. Using bare variables is deprecated.
   solved: update playbook
3. use git module
4. To save time, turning Off Facts on localhost.

Since https://gerrit.opnfv.org/gerrit/#/c/20661/ is under codereview,
for qtip ci job, I temporarily modify function write_to_file() in
env_setup.py.

Change-Id: I71a08ebf87cd8c8d851a3f8f760e29e8725f0e0f
Signed-off-by: wu.zhihui <wu.zhihui1@zte.com.cn>