Since eZ5.0, legacy cleanuphandlers can not tell anymore if they're been run in the context of:

• an ezexecution::cleanexit call (most likely when a custom view does that)
• the ezpkernelweb::run() method - which could happen multiple time during a single page load

I propose to add a flag, passed as 1st parameter to cleanup handlers, to let them be able to tell the difference, as some might want to do different things for the 2 different usages