Bug 10893: fix location facet in UNIMARC

Bug 10893: fix location facet in UNIMARC

Location facet in UNIMARC is void. In the code, it is build
on 995$c, while location is store in 995$e (see record.abs).
This patch replace 995$c with 995$e in Koha.pm

To test :
1. Use a UNIMARC Koha instance with ONE branch, and SEVERAL
    locations
2. Make a search in opac and staff interface : no location
    facet on the left side of the screen
3. apply the patch
4. Make the same search : location facets will be displayed

NOTE: I, Mark Tompsett, rebased this. I confirmed that 995$c
      should be 995$e (wiki, Holdings_data_fields_(9xx) page)
      Also note that the code relocated based on bug 10078,
      causing the patch to not apply.

Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
NOTE: The location facet did not appear in master, but after
      applying the patch, it did appear.
      Because of the code being moved, it is no longer affected
      by the branch count or singleBranchMode.

Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Fixes wrong subfield code for UNIMARC.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>
(cherry picked from commit 81cc05cbd6ea31151a03989edd1ffb3f775c3582)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>