Correct assignment of energy to tracks in the HMS.

Correct association of clusters of calorimeter hits to tracks in the HMS. Affected subroutines are h_clusters_cal and h_tracks_cal. Clusters with zero energy deposition are eliminated from the association by assigning them a coordinate out of reach of tracks in h_clusters_cal. Linking of the closest to track cluster is corrected and simplified in h_tracks_cal. The corrected code was checked against hcana.