svl: don't forget about big-endian parts in filerec.cxx

Fixes:
  (build error) filerec.cxx:591: error: no match for 'operator>>'

Change-Id: I412cc9121c50830069e8e71c35dfb4f8ce475357
Reviewed-on: https://gerrit.libreoffice.org/8206
Tested-by: Michael Stahl <mstahl@redhat.com>
Reviewed-by: Michael Stahl <mstahl@redhat.com>