Remove underscore from classes RevDel_*

Part of program to remove underscores from class names. Checked core and
675 extensions for occurrences. All uses are in core in core are updated
in this patch. There are no uses in Gerrit extensions.

Change-Id: Ibad9afb9c696da894dab6b34ea14fb62642573ad
Merge "Remove underscore from classes RevDel_*"