ipapython: Clean up krb5_error
    
    `krb5_error` has different definition in MIT krb.
    https://web.mit.edu/kerberos/krb5-latest/doc/appdev/refs/types/krb5_error.html
    
    > Error message structure.
    >
    > Declaration:
    > typedef struct _krb5_error krb5_error
    
    While `krb5_error_code`
    https://web.mit.edu/kerberos/www/krb5-latest/doc/appdev/refs/types/krb5_error_code.html#c.krb5_error_code
    
    > krb5_error_code
    > Used to convey an operation status.
    >
    > The value 0 indicates success; any other values are com_err codes. Use krb5_get_error_message() to obtain a string describing the error.
    >
    > Declaration
    > typedef krb5_int32 krb5_error_code
    
    And this is what was actually used.
    
    To prevent confusion of types `krb5_error` was replaced with
    `krb5_error_code`.
    
    Fixes: https://pagure.io/freeipa/issue/9519
    Signed-off-by: Stanislav Levin <slev@altlinux.org>
    Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>