Non-SFI mode: Make nacl_helper_nonsfi build depend on libnacl_sys_private.a
Non-SFI mode: Make nacl_helper_nonsfi build depend on libnacl_sys_private.a

Otherwise nacl_helper_nonsfi is not rebuilt when
libnacl_sys_private.a has been changed.

BUG= https://code.google.com/p/chromium/issues/detail?id=358465
TEST=# In Chromium repository
     touch native_client/src/nonsfi/linux/linux_pthread_private.c &&
     ninja -C out/Release nacl_helper_nonsfi

Review URL: https://codereview.chromium.org/755753005

git-svn-id: 721b910a23eff8a86f00c8fd261a7587cddf18f8@14202 fcba33aa-ac0c-11dd-b9e7-8d5594d729c2

sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client