Prevent PrForwardTracking from using fake qoverP

Currently, when input tracks' qOverP != 0 , ForwardTracking considers them as PrVeloUT tracks with momentum estimate, However, there is plan to set a default qOverP value to PrPixelTracking's output tracks, the qOverP != 0 may no longer be a good indication. This update tries to fix the problem. There should be no influence on physics performance.

When the input tracks are from PrPixelTracking, or you don't want to use momentum estimate from input tracks, set PrForwardTool().UseMomentumEstimate = False

@cattanem @decianm @sstahl @chasse @rquaglia