named: Don't override custom command line options for named
    
    Custom options can be supplied by a vendor via 'OPTIONS' env
    variable(platform specific) and IPA installer will override them
    in this case. Thus, at least, the base parsing of existing options
    is required.
    
    Current named command line options:
    NS_MAIN_ARGS "46A:c:C:d:D:E:fFgi:lL:M:m:n:N:p:P:sS:t:T:U:u:vVx:X:"
    
    If there are several same options the last passed wins.
    
    Fixes: https://pagure.io/freeipa/issue/8094
    Signed-off-by: Stanislav Levin <slev@altlinux.org>
    Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>
    Reviewed-By: Christian Heimes <cheimes@redhat.com>