Bug#823750: Already fixed

https://bugs.launchpad.net/ubuntu/+source/imagemagick/+bug/1553366

Bug#823750: Already fixed

https://bugs.launchpad.net/ubuntu/+source/imagemagick/+bug/1542112 is fixed by previous commit

Bug#823750: Already fixed by previous commit

https://bugs.launchpad.net/ubuntu/+source/imagemagick/+bug/1539067 is already fixed

Bug#823750: Already fixed by previous commit

https://bugs.launchpad.net/ubuntu/+source/imagemagick/+bug/1542106