Override web.xml context init param
While testing we can't use the application.properties defined in web.xml.  I have not
found a way to override the setting when embedding jetty.  It can be done via
web-overrides.xml or jetty.xml, but this solution is much simpler.  I just set a ThreadLocal
from the test setup class that overrides reading the init-param from web.xml during the
servlet configuration.