[evlatests] Source change flagging

[Walter Brisken]

I have fixed IDCAFs flagging problem.  Before the fix all flags got 
forgotten at the start of a source change because I clogged the alert 
parser with some HTTP preamble data and any existing flags would not be 
reinstated.  Now that I skip over this preamble things are all good.  The 
problem began when I stopped using wget to retrieve data from the alert 
server and instead embedded an HTTP interface into idcaf.  Please continue 
to report any suspect flagging to me.

-Walter