make sure IPA_CONFDIR is used to check that client is configured

Fixes a test ipatests/test_cmdline/test_cli.py:test_cli_fs_encoding()
which sets IPA_CONFDIR and attempts to interpret the resulting error
message. However, if the test is run on an enrolled machine (a
developer's laptop, for example), check_client_configuration() will
succeed because it ignores IPA_CONFDIR and, as result, api.finalize()
will fail later with a stacktrace.

Pass an environment object and test an overridden config file existence
in this case to fail with a proper and expected message.

Reviewed-By: Christian Heimes <cheimes@redhat.com>

ipalib/cli.py

@@ -1454,7 +1454,7 @@ def run(api):
         (_options, argv) = api.bootstrap_with_global_options(context='cli')
 
         try:
-            check_client_configuration()
+            check_client_configuration(env=api.env)
         except ScriptError as e:
             sys.exit(e)