repobuild/precise: Get libzmq3 from trusty and not from precise

libzmq3 needs to be later than the version available for precise;
just grab it from trusty, which requires excluding it from the
precise updates, and adding a trusty distribution and an update
rule for it.

Signed-off-by: Dan Mick <dan.mick@inktank.com>
repobuild: Remove obsolete Makefile comments

Signed-off-by: Dan Mick <dan.mick@inktank.com>
repobuild/conf/*: suppress errors for not having keys, InRelease

Signed-off-by: Dan Mick <dan.mick@inktank.com>
repobuild/wheezy: get jessie libzmq3, not wheezy

Same as was just implemented for precise to get trusty's libzmq3

Signed-off-by: Dan Mick <dan.mick@inktank.com>
repobuild: reprepro on precise doesn't support GetInRelease

Signed-off-by: Dan Mick <dan.mick@inktank.com>

Closes 198