ipa: ensure updown_cb() gets called on reconnect
ipa: ensure updown_cb() gets called on reconnect

If the ipa_client_conn is lost and ther user issues a new
ipa_client_conn_open(), then we need to re-set our internal state
to IPA_CLIENT_LINK_STATE_CONNECTING, as otherwise we wouldn't call the
updown_cb() once the link is up again.

osmocom/libosmo-abis,osmocom/libosmo-abis,telenoobie/libosmo-abis,telenoobie/libosmo-abis,osmocom/libosmo-abis