Add missing dependency for //sandbox/linux:seccomp_starter_android

Commit 5fb31977 added this new target but
didn't depend on the //sandbox:sandbox_features target so it failed to
compile:

In file included from ../../sandbox/linux/seccomp-bpf-helpers/seccomp_starter_android.cc:5:                                                                       
../../sandbox/linux/seccomp-bpf-helpers/seccomp_starter_android.h:10:10: fatal error: 'sandbox/sandbox_features.h' file not found                                 
#include "sandbox/sandbox_features.h"                                                                                                                             

NOTRY=true

Bug: 742028
Bug: 730066
Bug: 739879
Change-Id: Ib0bc9f34f0cbf35be0f9f3cf412cd0fdcf678f3f
Reviewed-on: https://chromium-review.googlesource.com/570514
Commit-Queue: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
Reviewed-by: Glenn Hartmann <hartmanng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#486479}

sandbox/linux/BUILD.gn

@@ -284,6 +284,7 @@ if (is_android) {
 
     deps = [
       "//base",
+      "//sandbox:sandbox_features",
     ]
 
     if (use_seccomp_bpf) {