Fix and test python scripts and kerberos

This fixes up the python credentials interface in a number of areas,
with the aim of supporting '-k yes' as a command line option.  (This
enables the use of kerberos).

As such, I've had to change the get_credentials call to take a
loadparm context, so that the credentials can be initialised
correctly.

The test_kinit script has been modified to prove that this continues
to work, as well as to provide greater code coverage of the kerberos
paths.

Andrew Bartlett
(This used to be commit 727ef40c2b)

source4/scripting/python/samba/getopt.py

@@ -18,7 +18,7 @@
 #
 
 import optparse
-from credentials import Credentials
+from credentials import Credentials, AUTO_USE_KERBEROS, DONT_USE_KERBEROS, MUST_USE_KERBEROS
 
 class SambaOptions(optparse.OptionGroup):
     def __init__(self, parser):
@@ -65,6 +65,9 @@ class CredentialsOptions(optparse.OptionGroup):
                         help="Workgroup", callback=self._parse_workgroup)
         self.add_option("-N", "--no-pass", action="store_true",
                         help="Don't ask for a password")
+        self.add_option("-k", "--kerberos", metavar="KERBEROS", 
+                        action="callback", type=str,
+                        help="Use Kerberos", callback=self._set_kerberos)
         self.creds = Credentials()
 
     def _parse_username(self, option, opt_str, arg, parser):
@@ -76,11 +79,17 @@ class CredentialsOptions(optparse.OptionGroup):
     def _set_password(self, option, opt_str, arg, parser):
         self.creds.set_password(arg)
 
+    def _set_kerberos(self, option, opt_str, arg, parser):
+        if bool(arg) or arg.lower() == "yes":
+            self.creds.set_kerberos_state(MUST_USE_KERBEROS)
+        else:
+            self.creds.set_kerberos_state(DONT_USE_KERBEROS)
+
     def _set_simple_bind_dn(self, option, opt_str, arg, parser):
         self.creds.set_bind_dn(arg)
 
-    def get_credentials(self):
-        self.creds.guess()
+    def get_credentials(self, lp):
+        self.creds.guess(lp)
         if not self.no_pass:
             self.creds.set_cmdline_callbacks()
         return self.creds