Remove ICS getSessionId constructor

getSessionId isn't exported anymore, we can't inherit it from
AudioTrack

Change-Id: I1b8c4de88900343d5683a370da2bf94fe5c70326
diff --git a/media/libmedia/AudioTrack.cpp b/media/libmedia/AudioTrack.cpp
index bf7d179..fe5cd9e 100644
--- a/media/libmedia/AudioTrack.cpp
+++ b/media/libmedia/AudioTrack.cpp
@@ -788,11 +788,6 @@
     }
 }
 
-extern "C" int _ZNK7android10AudioTrack12getSessionIdEv();
-extern "C" int _ZN7android10AudioTrack12getSessionIdEv() {
-    return _ZNK7android10AudioTrack12getSessionIdEv();
-}
-
 status_t AudioTrack::attachAuxEffect(int effectId)
 {
     AutoMutex lock(mLock);