[Mesa-ci-intel] Update piglit branch for 18.2 branch (including staging branches)

[Juan A. Suarez Romero]

Hi.

Mesa commit e0837f061a6 ("egl/dri: fix error value with unknown drm format")
fixes returned with an unknown drm format.

This was fixed in piglit too, in commit c79d8d223
("EGL_EXT_image_dma_buf_import: fix error check with unknown drm format").


The Mesa commit has been cherry-picked for 18.2, but the piglit branch used as
reference does not have the piglit fix.

Hence, we need to update the piglit branch to that commit or newer, to avoid
errors.

Maybe this need to be done also for other branches.


Thanks in advance!


	J.a