kerberos: Remove un-used event context argument from smb_krb5_init_context()

kerberos: Remove un-used event context argument from smb_krb5_init_context()

The event context here was only specified in the server or admin-tool
context, which does not do network communication, so this only caused
a talloc_reference() and never any useful result.

The actual network communication code sets an event context directly
before making the network call.

Andrew Bartlett

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
Autobuild-User(master): Andrew Bartlett <abartlet@samba.org>
Autobuild-Date(master): Mon Apr 28 02:24:57 CEST 2014 on sn-devel-104