project = Iredmail.objects.get(id=id)

ssh_crt_name = project.ssh_crt

if request.method == 'POST':

    file_obj = request.FILES.get("ssh_crt", "")

    i_form = IredmailForm(request.POST,request.FILES,instance=project)

    if i_form.is_valid():

        obj = i_form.save(commit=False)

        if file_obj == "":

            obj.ssh_crt = ssh_crt_name

        obj.save()