vg_common_svg : Initialize "display" attribute

Summary:
In e850e3e, the code to initialize this property is missing.
That makes the object invisible when printing svg through edje.
This is a patch to fix it.
@fix

Test Plan: N/A

Reviewers: Hermet, smohanty, kimcinoo

Reviewed By: Hermet

Subscribers: cedric, reviewers, committers

Tags: efl

Differential Revision: https://phab.enlightenment.org/D9833