[eclipse-pmc] Removal of the return value of AbstractStatusHandler#handl

[Tod Creasey <Tod_Creasey@xxxxxxxxxx>]

REQUEST 
Change of the following API 

boolean AbstractStatusHandler#handle(StatusAdapter) 
to 
void AbstractStatusHandler#handle(StatusAdapter) 

boolean WorkbenchErrorHandler#handle(StatusAdapter)
to 
void WorkbenchErrorHandler#handle(StatusAdapter) 

GOALS/BENEFITS: 
The returnValue is misleading as we
do not handle the invoking of other handlers in the system by default any
more.

RISKS
No known risks as we are currently the only consumers. 

Affected bugs 
https://bugs.eclipse.org/bugs/show_bug.cgi?id=175552