auth/credentials/tests: Python 3.6 avoid deepcopy error

In PY3 both deepcopy & (shallow)copy fail with

  Traceback (most recent call last):
    File "auth/credentials/tests/bind.py", line 42, in <module>
      creds_machine = copy.copy(creds)
    File "/usr/lib64/python3.6/copy.py", line 96, in copy
      rv = reductor(4)
  TypeError: can't pickle credentials.Credentials objects

This patch avoids the nasty copies but creating and populating the
Credential objects instead of copying

Signed-off-by: Noel Power <[email protected]>
Reviewed-by: Andrew Bartlett <[email protected]>

auth/credentials/tests/bind.py

@@ -19,6 +19,13 @@
 from samba import gensec
 import samba.tests
 from samba.tests import delete_force
+from samba.credentials import Credentials
+
+def create_credential(lp, other):
+    c = Credentials()
+    c.guess(lp)
+    c.set_gensec_features(other.get_gensec_features())
+    return c
 
 parser = optparse.OptionParser("ldap [options] <host>")
 sambaopts = options.SambaOptions(parser)
@@ -39,12 +46,12 @@
 lp = sambaopts.get_loadparm()
 creds = credopts.get_credentials(lp)
 creds.set_gensec_features(creds.get_gensec_features() | gensec.FEATURE_SEAL)
-creds_machine = copy.deepcopy(creds)
-creds_user1 = copy.deepcopy(creds)
-creds_user2 = copy.deepcopy(creds)
-creds_user3 = copy.deepcopy(creds)
-creds_user4 = copy.deepcopy(creds)
 
+creds_machine = create_credential(lp, creds)
+creds_user1 = create_credential(lp, creds)
+creds_user2 = create_credential(lp, creds)
+creds_user3 = create_credential(lp, creds)
+creds_user4 = create_credential(lp, creds)
 
 class BindTests(samba.tests.TestCase):