Description of problem:
Deploy logging 3.7, ansible threw out error

fatal: [###############]: FAILED! => {"failed": true, "msg": "the field 'args' has an invalid value, which appears to include a variable that is undefined. The error was: 'openshift_client_binary' is undefined\n\nThe error appears to have been in '/usr/share/ansible/openshift-ansible/roles/openshift_logging_fluentd/tasks/main.yaml': line 208, column 3, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n# We need to pause between nodes while labeling to avoid overloading the scheduler.\n- name: Label OCP nodes for Fluentd\n  ^ here\n"}

Version-Release number of selected component (if applicable):
openshift-ansible-3.7.58-1.git.37.6db1e6f.el7.noarch

How reproducible:
Always

Steps to Reproduce:
1. Deploy logging 3.7
2.
3.

Actual results:
Logging installation failed at TASK [openshift_logging_fluentd : Label OCP nodes for Fluentd]

Expected results:
Installation is successfully

Additional info:
openshift_logging_install_logging=true
openshift_logging_image_prefix=${IMAGE_PREFIX}
openshift_logging_image_version=v3.7