Fix flag parsing in pnacl-nm.
Fix flag parsing in pnacl-nm.

This fixes a translator build failure (via call in prune_test.py)

BUG=None
R=jvoung@chromium.org

Review URL: https://codereview.chromium.org/18103004

git-svn-id: 721b910a23eff8a86f00c8fd261a7587cddf18f8@11660 fcba33aa-ac0c-11dd-b9e7-8d5594d729c2

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