check git merge: use outstanding commits, not time

Using timestamps for this check could get us in all sorts of edge
cases. What is now checked instead is just the number of outstanding
commits in the remote branch we track.

If this is higher than 0, a critical alert is raised. We can play with
notifications so that an irc notification happens after a
certain number of minutes (the 'interval' parameter).

Change-Id: I69498ff23e5ddf620a0ea6ea9843a7bd947f10a3
Signed-off-by: Giuseppe Lavagetto <glavagetto@wikimedia.org>
analytics-kafka partman didn't work, it was too complicated

revert back to raid1-30G.

Change-Id: I459710953a5fbf9d8fc5a988a2aa2d672c92ed7f
Merge "check git merge: use outstanding commits, not time" into production