Increase the limit on certain geni-get response lengths (esp. manifests).
Increase the limit on certain geni-get response lengths (esp. manifests).

The old limit (2K) was big enough that essentially any hand-written
rspec would work fine, but also small enough that pretty much any manifest
for a Flack-generated request rspec would fail.

nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome