imagemagick: bump version to 7.0.5-0 (security)

imagemagick: bump version to 7.0.5-0 (security)

- Fixed memory leak when creating nested exceptions in Magick++
  https://www.imagemagick.org/discourse-server/viewtopic.php?f=23&p=142634

- Fixed fd leak for webp coder
  https://github.com/ImageMagick/ImageMagick/pull/382

- Fixed Spurious memory allocation message
  https://www.imagemagick.org/discourse-server/viewtopic.php?f=3&t=31438

Full changelog: http://imagemagick.org/script/changelog.php

Signed-off-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>