Bug 13975: Remove compilation warning about encoding pragma deprecation

Bug 13975: Remove compilation warning about encoding pragma deprecation

Test plan:
0/ Does not apply the patch
1/ Launch the export_borrowers.pl script to export data with unicode characters
 % perl misc/export_borrowers.pl -w "borrowernumber=42" --field borrowernumber --field surname --field firstname
  Use of the encoding pragma is deprecated at misc/export_borrowers.pl
  7874,JOUBU,صةصةصة
2/ Apply this patch
3/ Repeat 1
 % perl misc/export_borrowers.pl -w "borrowernumber=42" --field borrowernumber --field surname --field firstname
  7874,JOUBU,صةصةصة

Note that the deprecated message is gone and the encoding is correct.

Signed-off-by: Frederic Demians <f.demians@tamil.fr>
  I confirm the warning (on Perl version above 5.14). And that the patch fix
  the warning.

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>
(cherry picked from commit dbd8602280192e4e4cd9915ad8c345a2d40dfb72)
Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>