sudo: bump to version 1.8.15

Unneeded patches removed. Highlights from ChangeLog:

* Fixed a build problem on systems that don't implicitly include
  sys/types.h from other header files. Bug #711.

* Fixed the compiler stack protector test in configure for compilers
  that support -fstack-protector but don't actually have the ssp
  library available.

Signed-off-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>