* gnu/packages/patches/icecat-CVE-2015-0797.patch,
  gnu/packages/patches/icecat-CVE-2015-2708-pt1.patch,
  gnu/packages/patches/icecat-CVE-2015-2708-pt2.patch,
  gnu/packages/patches/icecat-CVE-2015-2708-pt3.patch,
  gnu/packages/patches/icecat-CVE-2015-2708-pt4.patch,
  gnu/packages/patches/icecat-CVE-2015-2710-pt1.patch,
  gnu/packages/patches/icecat-CVE-2015-2710-pt2.patch,
  gnu/packages/patches/icecat-CVE-2015-2710-pt3.patch,
  gnu/packages/patches/icecat-CVE-2015-2713-pt1.patch,
  gnu/packages/patches/icecat-CVE-2015-2713-pt2.patch,
  gnu/packages/patches/icecat-CVE-2015-2716.patch: Remove files.
* gnu-system.am (dist_patch_DATA): Remove them.
* gnu/packages/gnuzilla.scm (icecat): Update to 31.7.0-gnu1.  Remove patches.