Clean up superfluous directories draco/src in include
Clean up superfluous directories draco/src in include

The way header files are glob resulted in two additional directories
being nested in include.

google/draco,google/draco,google/draco,louquillio/draco,louquillio/draco,louquillio/draco,google/draco,louquillio/draco,google/draco,louquillio/draco,google/draco,google/draco,louquillio/draco