gnu: icecat: Update to 31.4.0.
* gnu/packages/patches/icecat-CVE-2014-1587-bug-1042567.patch,
gnu/packages/patches/icecat-CVE-2014-1587-bug-1072847.patch,
gnu/packages/patches/icecat-CVE-2014-1587-bug-1079729.patch,
gnu/packages/patches/icecat-CVE-2014-1587-bug-1080312.patch,
gnu/packages/patches/icecat-CVE-2014-1587-bug-1089207.patch,
gnu/packages/patches/icecat-CVE-2014-1590.patch,
gnu/packages/patches/icecat-CVE-2014-1592.patch,
gnu/packages/patches/icecat-CVE-2014-1593.patch,
gnu/packages/patches/icecat-CVE-2014-1594.patch,
gnu/packages/patches/icecat-CVE-2014-8634-pt1.patch,
gnu/packages/patches/icecat-CVE-2014-8634-pt2.patch,
gnu/packages/patches/icecat-CVE-2014-8638-pt1.patch,
gnu/packages/patches/icecat-CVE-2014-8638-pt2.patch,
gnu/packages/patches/icecat-CVE-2014-8639.patch,
gnu/packages/patches/icecat-CVE-2014-8641.patch,
gnu/packages/patches/icecat-armhf-xpcom.patch: Remove files.
* gnu-system.am (dist_patch_DATA): Remove them.
* gnu/packages/gnuzilla.scm: Update to 31.4.0. Remove patches.