Fix /become?user_name=... under GWT debugger

We have to capture and include the gwt.codesvr query parameter
in our redirect location in order to get the UI to start up.
If we don't the module asks us to recompile it.

Change-Id: I3eba440ce584e5d0de56bba2a408b9174f1aa676
Signed-off-by: Shawn O. Pearce <sop@google.com>
1 file changed