gnu: icecat: Update to 31.6.0-gnu1.
* gnu/packages/patches/icecat-CVE-2015-0801.patch,
gnu/packages/patches/icecat-CVE-2015-0807.patch,
gnu/packages/patches/icecat-CVE-2015-0815-pt1.patch,
gnu/packages/patches/icecat-CVE-2015-0815-pt2.patch,
gnu/packages/patches/icecat-CVE-2015-0815-pt3.patch,
gnu/packages/patches/icecat-CVE-2015-0816.patch,
gnu/packages/patches/icecat-CVE-2015-0817.patch,
gnu/packages/patches/icecat-CVE-2015-0818-pt1.patch,
gnu/packages/patches/icecat-CVE-2015-0818-pt2.patch,
gnu/packages/patches/icecat-bug-1127780.patch,
gnu/packages/patches/icecat-bug-1145870.patch: Remove files.
* gnu-system.am (dist_patch_DATA): Remove them.
* gnu/packages/gnuzilla.scm (icecat): Update to 31.6.0-gnu1. Remove patches.