Remove some additional instances of krbV from ipa-client

Make two krbV imports conditional. These aren't used during a client
install so should cause no problems.

Also fix the client installer to use the new env option in ipautil.run.
We weren't getting the krb5 configuration set in the environment because
we were overriding the environment to set the PATH.

ticket 136

ipapython/config.py

@@ -20,7 +20,6 @@
 import ConfigParser
 from optparse import OptionParser, IndentedHelpFormatter
 
-import krbV
 import socket
 import ipapython.dnsclient
 import re
@@ -113,8 +112,13 @@ def __discover_config(discover_server = True):
     rl = 0
     try:
         if not config.default_realm:
-            krbctx = krbV.default_context()
-            config.default_realm = krbctx.default_realm
+            try:
+                # only import krbV when we need it
+                import krbV
+                krbctx = krbV.default_context()
+                config.default_realm = krbctx.default_realm
+            except ImportError:
+                pass
             if not config.default_realm:
                 return False