Fix traceback on Darwin with Python3

os.write() needs bytes objects on python3 while python2 can work with
either a byte or unicode string.  Mark the DUMMY_CA_CERT string as
a byte string so it will work.

Fixes #19265
Fixes #19266

lib/ansible/module_utils/urls.py

@@ -309,7 +309,7 @@ if not HAS_MATCH_HOSTNAME:
 # ca cert, regardless of validity, for Python on Mac OS to use the
 # keychain functionality in OpenSSL for validating SSL certificates.
 # See: http://mercurial.selenic.com/wiki/CACertificates#Mac_OS_X_10.6_and_higher
-DUMMY_CA_CERT = """-----BEGIN CERTIFICATE-----
+b_DUMMY_CA_CERT = b("""-----BEGIN CERTIFICATE-----
 MIICvDCCAiWgAwIBAgIJAO8E12S7/qEpMA0GCSqGSIb3DQEBBQUAMEkxCzAJBgNV
 BAYTAlVTMRcwFQYDVQQIEw5Ob3J0aCBDYXJvbGluYTEPMA0GA1UEBxMGRHVyaGFt
 MRAwDgYDVQQKEwdBbnNpYmxlMB4XDTE0MDMxODIyMDAyMloXDTI0MDMxNTIyMDAy
@@ -326,7 +326,7 @@ MUB80IR6knq9K/tY+hvPsZer6eFMzO3JGkRFBh2kn6JdMDnhYGX7AXVHGflrwNQH
 qFy+aenWXsC0ZvrikFxbQnX8GVtDADtVznxOi7XzFw7JOxdsVrpXgSN0eh0aMzvV
 zKPZsZ2miVGclicJHzm5q080b1p/sZtuKIEZk6vZqEg=
 -----END CERTIFICATE-----
-"""
+""")
 
 #
 # Exceptions
@@ -603,7 +603,7 @@ class SSLValidationHandler(urllib_request.BaseHandler):
 
         # Write the dummy ca cert if we are running on Mac OS X
         if system == 'Darwin':
-            os.write(tmp_fd, DUMMY_CA_CERT)
+            os.write(tmp_fd, b_DUMMY_CA_CERT)
             # Default Homebrew path for OpenSSL certs
             paths_checked.append('/usr/local/etc/openssl')