Reindex 'key_indicies' after item delete
    
    The "keys.splice(i, 1)" removes one item at the specified position
    from an array. Thus hashes which are stored at "that._key_indicies"
    are no longer valid and should be reindexed.
    
    Fixes: https://pagure.io/freeipa/issue/7678
    Reviewed-By: Serhii Tsymbaliuk <stsymbal@redhat.com>