[PATCH] -a command line option

The -a option was broken by some config updates early in the 3.x cycles
which reset SquidConfig prior to parsing but after opening the -a
provided port.

This patch preserves the documented -a behaviour of opening an HTTP
listener port from the command line.
It also adds the double port opening for split-stack systems, preserving
consistency with wildcard http_port entries in the config.

Overall, I'm not sure we actually need the -a option. Especially given
that it appears to have been a few years before anyone noticed its being
broken. What are peoples thoughts on deprecating it for removal in 3.3?

Amos

-- 
Please be using
   Current Stable Squid 2.7.STABLE9 or 3.1.9
   Beta testers wanted for 3.2.0.3