Fix error code check in releaseBuffer

BufferQueueConsumer can occasionaly return STALE_BUFFER_SLOT which
does not indicate an error but that there is no more to be done.
SurfaceFlingerConsumer should report and error only with a status
code inferior to zero.

Test: AUPT
Change-Id: Ie0624358301e1e3b090adf35facd6eac79c214db
diff --git a/services/surfaceflinger/SurfaceFlingerConsumer.cpp b/services/surfaceflinger/SurfaceFlingerConsumer.cpp
index 04f4f7e..2fcbdba 100644
--- a/services/surfaceflinger/SurfaceFlingerConsumer.cpp
+++ b/services/surfaceflinger/SurfaceFlingerConsumer.cpp
@@ -223,7 +223,7 @@
     status_t result = releaseBufferLocked(mPendingRelease.currentTexture,
             mPendingRelease.graphicBuffer, mPendingRelease.display,
             mPendingRelease.fence);
-    ALOGE_IF(result != NO_ERROR, "releasePendingBuffer failed: %s (%d)",
+    ALOGE_IF(result < NO_ERROR, "releasePendingBuffer failed: %s (%d)",
             strerror(-result), result);
     mPendingRelease = PendingRelease();
     return true;