new condition object (ZDC Low Gain Fraction) added for HCAL

new condition object named ZDC Low Gain Fraction was added for HCAL
In this case only one artificial event is being processed thus it does not cause a lot of harm. I just fallowed the pattern of other HCAL condition objects and this problem happens to be in all of them. But in the future we can solve this by adding a delete statement after writing to the database has been accomplished.