Remove the __init__ function in class AlertHandler, that is redundant

[joseph-v]

Issue/Feature Description: The init in class AlertHandler is redundant (delfin/drivers/dell_emc/vmax/alert_handler/unisphere_alerts.py)

Why this issue to fixed / feature is needed(give scenarios or use cases):

How to reproduce, in case of a bug:

Other Notes / Environment Information: (Please give the env information, log link or any useful information for this issue)