Restrict the version of connection
Restrict the version of connection

Verison 0.2.6 of the connection library switched from `Handle`s to
`Socket`s which resulted in a number of bizarre unintended side
effects like data leaking from TLS connections into HTTP responses.

Until 0.2.6 is fixed, we will lock connection to the previous
version.

ambiata/mismi,ambiata/mismi