Fix uses of KeyedVector

Constructor for AudioFlinger::mAudioHwDevs was missing, and so
AudioFlinger::findSuitableHwDev_l() could return an undefined pointer
if a non-0 module wasn't found.

A KeyedVector of Plain Old Data (POD) element type must specify the
default value in the constructor, or else the default will be undefined.

Minor:
 - Parameter had wrong type in constructor for AudioSystem::gOutputs.
 - Remove obsolete AudioSystem::gStreamOutputMap.

Change-Id: I9841493e018440e559d8b8b0e4e748ba2b2d365b
diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp
index 50179c5..c1ac77b 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -159,6 +159,7 @@
 AudioFlinger::AudioFlinger()
     : BnAudioFlinger(),
       mPrimaryHardwareDev(NULL),
+      mAudioHwDevs(NULL),
       mHardwareStatus(AUDIO_HW_IDLE),
       mMasterVolume(1.0f),
       mMasterMute(false),