ansible_ipa_client: Drop import of configure_nsswitch_database

configure_nsswitch_database has been removed with the freeipa commit

https://github.com/freeipa/freeipa/commit/41ef8fba31ddbb32e2e5b7cccdc9b582a0809111

The 4.4 compatibility hack leads to a ALREADY installed error in
ipaclient_test because of the removal. This affects ipaclient and
ipareplica roles and also the ipaclient deployment part in ipaserver.

configure_nsswitch_database is not used any more in ipaclient role modules
and therefore simply can be removed from ansible_ipa_client.