remove the usage of create_temporary_fifo from credential plugins

this resolves an issue that causes an endless hang on with Cyberark AIM
lookups when a certificate *and* key are specified

the underlying issue here is that we can't rely on the underyling Python
ssl implementation to *only* read from the fifo that stores the pem data
*only once*; in reality, we need to just use *actual* tempfiles for
stability purposes

see: https://github.com/ansible/awx/issues/6986
see: https://github.com/urllib3/urllib3/issues/1880

awx/main/credential_plugins/hashivault.py

@@ -3,16 +3,11 @@ import os
 import pathlib
 from urllib.parse import urljoin
 
-from .plugin import CredentialPlugin
+from .plugin import CredentialPlugin, CertFiles
 
 import requests
 from django.utils.translation import ugettext_lazy as _
 
-# AWX
-from awx.main.utils import (
-    create_temporary_fifo,
-)
-
 base_inputs = {
     'fields': [{
         'id': 'url',
@@ -101,8 +96,6 @@ def kv_backend(**kwargs):
         'timeout': 30,
         'allow_redirects': False,
     }
-    if cacert:
-        request_kwargs['verify'] = create_temporary_fifo(cacert.encode())
 
     sess = requests.Session()
     sess.headers['Authorization'] = 'Bearer {}'.format(token)
@@ -129,7 +122,9 @@ def kv_backend(**kwargs):
             path_segments = [secret_path]
 
     request_url = urljoin(url, '/'.join(['v1'] + path_segments)).rstrip('/')
-    response = sess.get(request_url, **request_kwargs)
+    with CertFiles(cacert) as cert:
+        request_kwargs['verify'] = cert
+        response = sess.get(request_url, **request_kwargs)
     response.raise_for_status()
 
     json = response.json()
@@ -157,8 +152,6 @@ def ssh_backend(**kwargs):
         'timeout': 30,
         'allow_redirects': False,
     }
-    if cacert:
-        request_kwargs['verify'] = create_temporary_fifo(cacert.encode())
 
     request_kwargs['json'] = {'public_key': kwargs['public_key']}
     if kwargs.get('valid_principals'):
@@ -170,7 +163,10 @@ def ssh_backend(**kwargs):
     sess.headers['X-Vault-Token'] = token
     # https://www.vaultproject.io/api/secret/ssh/index.html#sign-ssh-key
     request_url = '/'.join([url, secret_path, 'sign', role]).rstrip('/')
-    resp = sess.post(request_url, **request_kwargs)
+
+    with CertFiles(cacert) as cert:
+        request_kwargs['verify'] = cert
+        resp = sess.post(request_url, **request_kwargs)
 
     resp.raise_for_status()
     return resp.json()['data']['signed_key']