Bug 8064: Fix issues with control fields and non-repeatable check

Bug 8064: Fix issues with control fields and non-repeatable check

Fields < 010 were systematically unchecked during target rebuild because
they have no subfields (unchecking manually all subfields of a field
automatically uncheck the field)
When user check a field or a subfield, we have to uncheck it before
calling (sub)field_can_be_added. Otherwise, field is treated as if it
was already in target record, and this is a problem for non-repeatable
fields.

Signed-off-by: Bernardo Gonzalez Kriegel <bgkriegel@gmail.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>