ipa-client-install: Add 'debug' and 'show' statements to nsupdate commands

https://fedorahosted.org/freeipa/ticket/3629
Relax getkeytab test to allow additional messages on stderr

https://fedorahosted.org/freeipa/ticket/3633
Handle DIR type CCACHEs in test_cmdline properly

Pass a whole krbV.CCache object to ldap2 connect() method so that
it can properly detect both type and name of a CCAHE. Otherwise
the test fails on systems with default DIR type CCACHE.