Fix typo in build_files rule.
Fix typo in build_files rule.

TBR=leozwang@webrtc.org
TEST=watchlist.py

Review URL: http://webrtc-codereview.appspot.com/299011

git-svn-id: 917f5d3ca488f358c4d40eaec14422cf392ccec9@1115 4adac7df-926f-26a2-2b94-8c16560cd09d

mwgoldsmith/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,mwgoldsmith/ilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,mwgoldsmith/ilbc,TimothyGu/libilbc,TimothyGu/libilbc,mwgoldsmith/libilbc,ShiftMediaProject/libilbc,mwgoldsmith/ilbc,mwgoldsmith/libilbc,mwgoldsmith/ilbc,TimothyGu/libilbc,mwgoldsmith/libilbc,TimothyGu/libilbc