Fix singleton.h for qcom gralloc

Conflicts:
	include/utils/Singleton.h

Change-Id: I6d36faf5dab7c4724b2f97074ef1d6f623dda9fa
Revert "libgui: Use fences for all QCOM targets"

This reverts commit 055698a6f84c0830d3e6da2c510bd3e64fdb11ce.