Audioflinger: reverse logic of BT NREC indication

The interpretation of BT NREC by AudioFlinger to enable
or disable AEC and NS was wrong: NREC to ON (default) means
the phone (Audio Gateway) must enable local AEC and NS.

Change-Id: I88a264e7fc9831c43bbace4f6b585baec73f2006
diff --git a/services/audioflinger/AudioFlinger.h b/services/audioflinger/AudioFlinger.h
index 1141f6c..1ceb0ec 100644
--- a/services/audioflinger/AudioFlinger.h
+++ b/services/audioflinger/AudioFlinger.h
@@ -210,7 +210,7 @@
 
                 uint32_t    getMode() { return mMode; }
 
-                bool        btNrec() { return mBtNrec; }
+                bool        btNrecIsOff() { return mBtNrecIsOff; }
 
 private:
                             AudioFlinger();
@@ -1389,7 +1389,7 @@
                 DefaultKeyedVector< pid_t, sp<NotificationClient> >    mNotificationClients;
                 volatile int32_t                    mNextUniqueId;
                 uint32_t                            mMode;
-                bool                                mBtNrec;
+                bool                                mBtNrecIsOff;
 
                 Vector<AudioSessionRef*> mAudioSessionRefs;
 };