ipajoin.py

For ipa versions prior to 4.5 it is needed to use ipa-client-install script
as a source for functions. But the script contains a global finally clause
in which the generated ccache file gets removed. Threfore the script is
temporarily copied to ipa_client_install.py and the global finally clause
gets removed from the copy. All this is done in a temporary directory, which
gets removed right after the import has been done.

A Object called options is generated as ipa-client-install and also
ipaclient/install/client.py functions are using this object.

inspect.argspec is used on configure_krb5_conf to find out if the function
requires configure_sssd as an optional argument or in the options object.