ansible: disable python3_fact gathering as it's broken on el7
    
    el7 hosts don't have python3 installed normally, so this fact fails. ;(
    
    "failed_modules": {"python3_fact": {"failed": true, "module_stderr": "/usr/bin/env: python3: No such file or directory\n",
    
    So, lets just disable for now until we can fix it.
    
    Signed-off-by: Kevin Fenzi <kevin@scrye.com>