gnu: mupdf: Update to 1.12.0 [fixes CVE-2017-15369].

* gnu/packages/pdf.scm (mupdf): Update to 1.12.0.
[source]: Remove obsolete patches.
[inputs]: Add freeglut.
* gnu/packages/patches/mupdf-CVE-2017-14685.patch,
gnu/packages/patches/mupdf-CVE-2017-14686.patch,
gnu/packages/patches/mupdf-CVE-2017-14687.patch,
gnu/packages/patches/mupdf-CVE-2017-15587.patch: Delete files.
* gnu/local.mk (dist_patch_DATA): Remove them.
* gnu/packages/patches/mupdf-build-with-openjpeg-2.1.patch: Update and
rename to...
* gnu/packages/patches/mupdf-build-with-latest-openjpeg.patch: ... new file.