Bug#877668: if all "Hit"s, then apt-get update should return immediately

[積丹尼 Dan Jacobson <jidanni@jidanni.org>]

Package: apt
Version: 1.5
Severity: wishlist
File: /usr/bin/apt-get

Do "apt-get update" several times in a row.

# apt-get update
Hit:1 ...
Hit:2 ...
Reading package lists... Done
# apt-get update
Hit:1 ...
Hit:2 ...
Reading package lists... Done
# apt-get update
Hit:1 ...
Hit:2 ...
Reading package lists... Done

On a Cray, you won't notice the problem, but on smaller computers you
will notice that the command doesn't return right away, but instead does
the long "Reading package lists" step.

In fact that step is totally unnecessary, as we got all "Hit"s, so there
is nothing to update.