Fix build: incorrect revertion svgio

Incorrect revertion in commit 3d3401a6397e893808309ec374f5d8f890144906

Change-Id: If4abac2670b083ebbc75c2fe06ae9e100072ef00
Reviewed-on: https://gerrit.libreoffice.org/10466
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>