Conditionally import nss

python-nss does not exist (and is not needed) in RHEL8.
We need to conditionally import nss to avoid errors in RHEL8.

Change-Id: I699fbfab4c2106f24260c99905b1bd40a8e683a8
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1758771

novajoin/configure_ipa.py

@@ -52,8 +52,6 @@ except ImportError:
 if version.NUM_VERSION >= 40500:
     from cryptography.hazmat.primitives import serialization
 
-import nss.nss as nss
-
 logger = logging.getLogger()
 
 allowed_chars = string.ascii_letters + string.digits
@@ -171,6 +169,8 @@ class NovajoinRole(object):
 
         NOTE: For IPA v4.4.0.
         """
+        import nss.nss as nss
+
         nss.nss_init_nodb()
         nss_db = certdb.NSSDatabase()