Bug 11313: supply empty value in mandatory comboboxs in MARC record editors

In biblio (or authority) record editing or creation, Bug 3727 added
an empty value to combobox for subfields using itemtype authorized values,
which is mandatory and does not have a default value. This to avoid
selecting arbitrarily the first value of the combobox.

This patch extends this behavior to normal authorized values like CCODE,
COUNTRY ...

Also, when record already exists and has a defined value for the subfield
this value will be selected in combobox so there is no need for an empty
value.

Test plan :
- In a biblio framework, set a subfield mandatory and using itemtypes
  authorised values
- Set a default value for this subfield
- Create a new record with the framework
=> You see the subfield with a combobox, the first empty value is selected
- Go to biblio framework and set a default value for the subfield
- Create a new record with the framework
=> You see the subfield with a combobox, the default value is selected
   and there is no empty value
- Select an other value and save the record
- Edit this record
=> You see the subfield with a combobox, the saved value is selected and
   there is no empty value

Perform same tests with a normal authorized values categorie (instead of
  itemtypes).
Perform same tests with with authority creation/edition
Perform same tests with a normal authorized values categorie and authority
  creation/edition

Signed-off-by: David Cook <dcook@prosentient.com.au>

Works as described.

Fridolyn: I had a lot of difficulty understanding your test plan,
especially since the second line should not be in the test plan
(since if there is a default value, no empty value should appear).

Perhaps it would be useful to use more whitespace to separate
steps and the things for which a tester should check.

Also, it might be useful to specify what testers should check for
before and after applying the patch, so that they're sure that the
behaviour has been corrected.

In any case, the patch works! Certainly a helpful addition.

Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Passes all tests and QA script.

1) Adding a bibliographic record
Subfield is mandatory, no default value:
- adding record: no value is preselected, empty value exists
- editing record: saved value is shown,  empty value exists
Subfield is mandatory, defined default value:
- adding record: default is preselected, no empty value
- editing record: saved value is shown, no empty value exists
Subfield is not mandatory, defined default value:
- adding record: default is preselected, empty value exists
- editing record: saved value is shown, emtpy value exists
Subfield is not mandatory, no default value:
- adding record: empty value is preselected
- editing record: saved value is shown, empty value exists

2) Adding an authority record
Repeating tests from above.
- Subfield is mandatory, no default value: OK
- Subfield is mandatory, defined default value: OK
- Subfield is not mandatory, defined default value: OK
- Subfield is not mandatory, no default value: OK

Signed-off-by: Galen Charlton <gmc@esilibrary.com>