Bug 22154: Fix search for Braille from Advanced search page

Bug 22154: Fix search for Braille from Advanced search page

When you do an advanced search and choose the Format subtype
Braille, it looks for l-format:fk, but that is not the right
code for Braille.

fk does not exist. It should be fb for Tactile material/Braille
OR tc for Text/Braille

To test:
0) Catalog 2 records, one with 007 tc and another with fb
   Use value builder to verify both are for Braille.
1) In Administration > System preferences, make sure 'Subtypes'
   is checked in either OpacAdvSearchMoreOptions or OpacAdvSearchOptions
2) Go to Advanced search
3) If necessary, click on 'More options'
4) In the 'Subtype limits' section, choose 'Braille' from the 'Format'
   drop-down menu
5) Click on 'Search'
6) Verify both records were found

Signed-off-by: Michal Denar <black23@gmail.com>
Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>