using localvar to manage iRules process flow

Before reading a variable it must be set somewhere or an exception will occur. In the first iRule, add a "set stop_processing 0" before the switch statement so it will always be set to some value. Another approach is to bullet proof the second iRule test with something like

if {[catch {set stop_processing}] or $stop_processing != 1} { do stuff }}

which survive if the first iRule is not in the chain of execution.