Fail on unknown Command options

When unknown keyword arguments are passed to a Command, raise an
error instead of ignoring them.

Options used when IPA calls its commands internally are listed
in a new Command attribute called internal_options, and allowed.

Previous patches (0b01751c, c45174d6, c5689e7f) made IPA not use
unknown keyword arguments in its own commands and tests, but since
that some violations were reintroduced in permission_find and tests.
Fix those.

Tests included; both a frontend unittest and a XML-RPC test via the
ping plugin (which was untested previously).

https://fedorahosted.org/freeipa/ticket/2509

tests/test_cmdline/test_cli.py

@@ -128,8 +128,7 @@ class TestCLIParsing(object):
     def test_dnsrecord_del_all(self):
         try:
             self.run_command('dnszone_add', idnsname=u'test-example.com',
-                idnssoamname=u'ns.test-example.com',
-                admin_email=u'devnull@test-example.com', force=True)
+                idnssoamname=u'ns.test-example.com', force=True)
         except errors.NotFound:
             raise nose.SkipTest('DNS is not configured')
         try:
@@ -162,8 +161,7 @@ class TestCLIParsing(object):
     def test_dnsrecord_del_one_by_one(self):
         try:
             self.run_command('dnszone_add', idnsname=u'test-example.com',
-                idnssoamname=u'ns.test-example.com',
-                admin_email=u'devnull@test-example.com', force=True)
+                idnssoamname=u'ns.test-example.com', force=True)
         except errors.NotFound:
             raise nose.SkipTest('DNS is not configured')
         try: