Fix NaCl compilation
Fix NaCl compilation

nethelpers.cc was using LOG() but didn't include logging.h

R=wu@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/6829005

Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 4625df3e3eab6634fc1521a6735f3f6c20f9b882

sippet/talk,sippet/talk,sippet/talk,sippet/talk,sippet/talk