use minimal chroots for rebootstrap

This should reduce io-load on jenkins by not installing unneeded stuff.
rebootstrap: new architectures

 * sh4 succeeds in gcc dance
 * mips64el suggested by Aurelien Jarno
rebootstrap: new architectures

 * sh4 succeeds in gcc dance
 * mips64el suggested by Aurelien Jarno
fork chroot-run.sh for rebootstrap to test squid3

Also avoids installing tons of unneeded deps.
Revert "fork chroot-run.sh for rebootstrap to test squid3"

squid3 shows the very same symptoms as squid2.

This reverts commit 3d150e20f0267edf70923247d3c3fca2195f9dc8.
attempt to fix squid via refresh patterns
Merge commit 'fd94a8edc5c5a4d884f41f13e528dc2136950f47'
Unset http_proxy due to bug in cabal

(in haskell-http to be precise).
Revert "Unset http_proxy due to bug in cabal"

This reverts commit 0eac7a78d6862013ea47d7271f979b33286e2432. Lets see
if the bug has been fixed.
Merge remote-tracking branch 'helmut/rebootstrap'
Use squid3 in cabal-install

There is a bug that is triggered by using squid2
(https://github.com/haskell/HTTP/issues/68) and helmut found out that it
does not happen with squid3. Hence use squid3.
Plot: Do not use exclusion, to avoid bug
haskell-package-plan: Remove “totals” graph, due to Jenkins bug
Copy stats.csv in cleanup
Use the correct binary packages for the chromium browser
rebootstrap: sh4 does not have multilib

This commit removes the job rebootstrap_sh4_gcc49_nobiarch.
slow down when debootstrap fails

When one debootstrap fails, chroot-run finishes very quickly. That way a
temporary network failure quickly eats the whole jenkins job queue
producing large numbers of false errors. Rather delay such failures,
hoping that they healed themselves after the delay.
chroot-run.sh: be verbose about the amount of time we sleep
import squid3.conf from jenkins.d.n
squid3: raise object size limits