Description of problem: ipa-winsync-migrate: Traceback should be fixed with
proper console output

Version-Release number of selected component (if applicable):
ipa-server-trust-ad-4.2.0-15.el7_2.10.x86_64
ipa-server-4.2.0-15.el7_2.10.x86_64

How reproducible:Always.

Steps to Reproduce:
1. Ensure ipa related rpms are installed.
2. Ensure ipa-server-install is not run.
3. Now try to run command 'ipa-replica-prepare' and check console output.
4. Now try to run command 'ipa-winsync-migrate' and check console output.

Actual results:

Step3:
[root@host2 ipa-idoverride]# ipa-replica-prepare
IPA is not configured on this system.

Step4:
[root@host2 ~]# ipa-winsync-migrate
ipa: WARNING: session memcached servers not running
Traceback (most recent call last):
  File "/usr/sbin/ipa-winsync-migrate", line 23, in <module>
    WinsyncMigrate.run_cli()
  File "/usr/lib/python2.7/site-packages/ipapython/admintool.py", line 124, in
run_cli
    sys.exit(cls.main(sys.argv))
  File
"/usr/lib/python2.7/site-packages/ipaserver/install/ipa_winsync_migrate.py",
line 346, in main
    api.Backend.ldap2.connect(ccache)
  File "/usr/lib/python2.7/site-packages/ipalib/backend.py", line 63, in
connect
    conn = self.create_connection(*args, **kw)
  File "/usr/lib/python2.7/site-packages/ipaserver/plugins/ldap2.py", line 149,
in create_connection
    client_controls=clientctrls)
  File "/usr/lib/python2.7/site-packages/ipapython/ipaldap.py", line 1070, in
gssapi_bind
    '', auth_tokens, server_controls, client_controls)
  File "/usr/lib64/python2.7/contextlib.py", line 35, in __exit__
    self.gen.throw(type, value, traceback)
  File "/usr/lib/python2.7/site-packages/ipapython/ipaldap.py", line 975, in
error_handler
    error=info)
ipalib.errors.NetworkError: cannot connect to 'ldap://localhost:389':

Expected results:
When IPA server is not installed/configured and when commands are run on the
console, they should display message like "IPA is not configured" instead of
displaying a traceback on the console.

All other command line options display proper message on the console.

Additional info: