IPA: Initialize a boolean control value
    
    without this patch, valgrind was reporting:
    ==30955== Conditional jump or move depends on uninitialised value(s)
    ==30955== at 0xDBBACC3: ipa_subdomains_slave_search_done (ipa_subdomains.c:1111)
    ==30955== by 0xE73B34D: sdap_search_bases_ex_done (sdap_ops.c:222)
    ==30955== by 0xE6FFA98: sdap_get_generic_done (sdap_async.c:1872)
    ==30955== by 0xE6FF4E2: generic_ext_search_handler (sdap_async.c:1689)
    ==30955== by 0xE6FF840: sdap_get_and_parse_generic_done (sdap_async.c:1797)
    ==30955== by 0xE6FEFB5: sdap_get_generic_op_finished (sdap_async.c:1579)
    ==30955== by 0xE6FB1D2: sdap_process_message (sdap_async.c:353)
    ==30955== by 0xE6FAD51: sdap_process_result (sdap_async.c:197)
    ==30955== by 0xE6FAA14: sdap_ldap_next_result (sdap_async.c:145)
    ==30955== by 0x8E157FF: tevent_common_loop_timer_delay (tevent_timed.c:341)
    ==30955== by 0x8E16809: epoll_event_loop_once (tevent_epoll.c:911)
    ==30955== by 0x8E14F09: std_event_loop_once (tevent_standard.c:114)
    ==30955==
    
    Resolves:
    https://fedorahosted.org/sssd/ticket/3213
    
    Reviewed-by: Fabiano Fidêncio <fidencio@redhat.com>