update runc binary to 1.1.15

diff: opencontainers/runc@v1.1.14...v1.1.15

Release notes:

- The -ENOSYS seccomp stub is now always generated for the native
  architecture that runc is running on. This is needed to work around some
  arguably specification-incompliant behaviour from Docker on architectures
  such as ppc64le, where the allowed architecture list is set to null. This
  ensures that we always generate at least one -ENOSYS stub for the native
  architecture even with these weird configs. (containerd#4391)
- On a system with older kernel, reading /proc/self/mountinfo may skip some
  entries, as a consequence runc may not properly set mount propagation,
  causing container mounts leak onto the host mount namespace. (containerd#2404, containerd#4425)
- In order to fix performance issues in the "lightweight" bindfd protection
  against [CVE-2019-5736], the temporary ro bind-mount of /proc/self/exe
  has been removed. runc now creates a binary copy in all cases. (containerd#4392, containerd#2532)

Signed-off-by: Samuel Karp <[email protected]>

script/setup/runc-version

@@ -1 +1 @@
-v1.1.14
+v1.1.15