Add 1 to the raw HCAL HTR fiber number for HTR histogram firmware unpacking.

When unpacking data written with standard HCAL HTR firmware, the HTR fiber number from the raw data has 1 added to it so that the fiber numbers go from 1-8 "offline."  This patch does the same for raw data written with the HTR histogramming-mode firmware (for recent histogram firmware versions).  Previously this was not the case, leading to confusion and some complications when reading data written by the histogram firmware.