SurfaceFlinger: mFbProducerSlot initailization

b/12487813

SurfaceFlinger crash is observed during simulation of
Secondary display

Note: change 14e8b01a761180250671f3d6494532d8bd04fa8e
removed the initialization leading to the crash when
simulating secondary display.  Restore the initialization
to solve the problem.

Change-Id: Iae5845fb82735e01de5cc0dc582d13c27e3c614f
Signed-off-by: mayank parshar <mayankp@broadcom.com>
Signed-off-by: Pierre Couillaud <pierre@broadcom.com>
diff --git a/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.cpp b/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.cpp
index e203903..d7fef8c 100644
--- a/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.cpp
+++ b/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.cpp
@@ -461,6 +461,7 @@
     mFbFence = Fence::NO_FENCE;
     mOutputFence = Fence::NO_FENCE;
     mOutputProducerSlot = -1;
+    mFbProducerSlot = -1;
 }
 
 status_t VirtualDisplaySurface::refreshOutputBuffer() {