Bug 13801: svc/bib - Set charset to utf-8 on printing header

Bug 13801: svc/bib - Set charset to utf-8 on printing header

Test plan:
0/ Add unicode characters on the record biblionumber=X
1/ go on http://<staff-interface>/cgi-bin/koha/svc/bib/X
2/ Confirm you have encoding issues
3/ Apply the patch
4/ Repeat 2
5/ Confirm that all is correctly encoded

Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Mason James <mtj@kohaaloha.com>
(cherry picked from commit ede633b71435976d49bc8323d1ea5446d189868e)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>