Initialize RecoX and RecoY to fix first node bug

[jdkio]

There's a bug where the RecoX of the first node of the kalman track will be initialized to 18314 .

Reco_Tree->Scan("KalmanPos:TrackHitTruePos", "", "entryrange=100,110");
***********************************************
*        0 *        0 *           *           *
*        1 *        0 *     18314 * -1503.153 *
*        1 *        1 * 0.9841747 * -2416.708 *
*        1 *        2 *     18153 *     18153 *
*        1 *        3 * -1475.746 * -1484.912 *

That value corresponds to TMS_Const::TMS_Thick_End (a z value) so I thought it was being set to the wrong number at some point. But that was a dead end. Turns out all kalman node RecoX and RecoY values were uninitialized, and for some reason RecoX defaults to that value. But then Predict sets the value to a new one for all nodes except node 0 (the loop starts at node 1). This fixes it by initializing the RecoX to the same as x, and same with RecoY and y.

root [1] Reco_Tree->Scan("KalmanPos:TrackHitTruePos", "", "entryrange=100,110");
***********************************************
*    Row   * Instance * KalmanPos * TrackHitT *
***********************************************
*        0 *        0 *           *           *
*        1 *        0 * -1491.766 * -1503.153 *
*        1 *        1 * -2340.117 * -2416.708 *
*        1 *        2 *     18153 *     18153 *
*        1 *        3 * -1475.746 * -1484.912 *
*        1 *        4 * -2330.354 * -2399.559 *

@LiamOS, maybe you know if there's a better prediction than that? This seems slightly off since it's not taking into account the particle's trajectory, and only setting it to the hit x and y