gnu: wpa-supplicant: Update to 2.5.

* gnu/packages/patches/wpa-supplicant-2015-2-fix.patch,
  gnu/packages/patches/wpa-supplicant-2015-3-fix.patch,
  gnu/packages/patches/wpa-supplicant-2015-4-fix-pt1.patch,
  gnu/packages/patches/wpa-supplicant-2015-4-fix-pt2.patch,
  gnu/packages/patches/wpa-supplicant-2015-4-fix-pt3.patch,
  gnu/packages/patches/wpa-supplicant-2015-4-fix-pt4.patch,
  gnu/packages/patches/wpa-supplicant-2015-4-fix-pt5.patch,
  gnu/packages/patches/wpa-supplicant-2015-5-fix.patch,
  gnu/packages/patches/wpa-supplicant-CVE-2015-1863.patch: Delete files.
* gnu-system.am (dist_patch_DATA): Remove them.
* gnu/packages/admin.scm (wpa-supplicant-minimal): Update to 2.5.
  Remove patches.