Add new env vars to pylint plugin

The vars api.env.host_princ and smb_princ where introduced a while ago.
Sometimes parallel linting complain about the attributes. Add both to
the list of known members in pylint_plugins.py.

Related: https://pagure.io/freeipa/issue/3999
Signed-off-by: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>

pylint_plugins.py

@@ -499,6 +499,7 @@ AstroidBuilder(MANAGER).string_build(textwrap.dedent(
     api.env.force_schema_check = False
     api.env.home = ''  # object
     api.env.host = ''
+    api.env.host_princ = ''
     api.env.http_timeout = 0
     api.env.in_server = False  # object
     api.env.in_tree = False  # object
@@ -524,6 +525,7 @@ AstroidBuilder(MANAGER).string_build(textwrap.dedent(
     api.env.script = ''  # object
     api.env.site_packages = ''  # object
     api.env.skip_version_check = False
+    api.env.smb_princ = ''
     api.env.startup_timeout = 0
     api.env.startup_traceback = False
     api.env.tls_ca_cert = ''  # object