fix for 13331 [Bug 13331] Subfield does not show in cataloging editor - if subfield...

fix for 13331 [Bug 13331] Subfield does not show in cataloging editor - if subfield is disabled in OPAC/enabled in Staff, via frameworks

to test...

1/ attempt to add a new bib in the cataloguing editor, default framewok
  - observe 245b subfield is visible in the editor, for tab 2

2/ uncheck the OPAC visibility for 245b, within the framework editor - then save

3/ repeat step 1/
  - observe that the 245b subfield has disappeared from the cataloguing editor!

4/ apply patch,

5/ repeat step 1/
  - observe that the 245b subfield now displays correctly in the cataloguing editor

note: this looks looks like a typo bug, that has been in koha for years

Signed-off-by: wajasu <matted@34813.mypacks.net>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>