Fix build error in NetEQ when disabling NETEQ_CNG_CODEC
Fix build error in NetEQ when disabling NETEQ_CNG_CODEC

An #ifdef guard was missing, which caused NetEQ not to compile
when NETEQ_CNG_CODEC was not defined. This is Issue 10 
(http://code.google.com/p/webrtc/issues/detail?id=10).
Review URL: http://webrtc-codereview.appspot.com/43002

git-svn-id: 917f5d3ca488f358c4d40eaec14422cf392ccec9@91 4adac7df-926f-26a2-2b94-8c16560cd09d

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