hotfix request - bump MM max_stale_days back to 7

[Matt Domsch]

Between alpha and beta freezes, I decreased the MM config value
max_stale_days from 7 to 2.  This causes MM to "forget" about old
repomd.xml data after 2 days instead of 7, which reduces how long a
mirror can be "stale" before being ignored by yum.

As we've slowed down releasing updates for existing releases, it can
be longer than 2 days between pushing updates.  In this case, we run
into the propogation delay between when content gets posted on the
master, MM picking it up an hour later, and then "drops" the
now-historical metadata that's older than 2 days - mirrors who haven't
updated within that hour get ignored by yum with a pretty loud error
message.

I've got a fix, but await end of change freeze to roll out a new MM
with the fix.  Until then, I'd like to return the config value back to
7 days, which papers over the propogation delay much better.

+1s please.

Thanks,
Matt

-- 
Matt Domsch
Technology Strategist
Dell | Office of the CTO