Efl.Gfx.Path: Modify boundary calculation.

Summary:
The point of the path is of type float.
The boundary must contain the coordinates of the point,
so min_x,y value must be round down and the max value round up.

Test Plan: N/A

Reviewers: Hermet, herb, kimcinoo

Reviewed By: Hermet

Subscribers: cedric, reviewers, committers

Tags: efl

Differential Revision: https://phab.enlightenment.org/D11917