When LLVM 3.5 was merged, the handling of errors was broken. This
is being fixed in the CL listed below. This CL fixes Subzero's
call so that it will work with the CL listed below.

Relavant LLVM CL: https://codereview.chromium.org/770853002

BUG= https://code.google.com/p/nativeclient/issues/detail?id=4006
R=jfb@chromium.org, stichnot@chromium.org

Review URL: https://codereview.chromium.org/775173002