fix(googleauth): use semanage instead of salt module

selinux.fcontext_policy_present only works once, if the policy is
already present the salt state errors, add an unless statement to
check if the policy is already in place.

Error:
  ----------
            ID: users_googleauth_selinux_present
      Function: selinux.fcontext_policy_present
          Name: /etc/google_authenticator.d(/.*)?
        Result: False
       Comment: Error adding new rule: {'pid': 10389, 'retcode': 1, 'stdout': '', 'stderr': 'ValueError: File context for /etc/google_authenticator.d(/.*)? already defined'}
       Started: 07:14:38.736705
      Duration: 609.271 ms
       Changes:

users/googleauth.sls

@@ -46,6 +46,7 @@ users_googleauth_selinux_present:
     - sel_user: unconfined_u
     - sel_type: ssh_home_t
     - sel_level: s0
+    - unless: "semanage fcontext -l | grep '{{ users.googleauth_dir }}(/.*)?' | grep ssh_home_t"
     - require:
         - pkg: policycoreutils-package
 {%-   endif %}