lpad not robust against transient errors from launchpad api

[Martin Packman]

Using lbox, I just had the following error interacting with launchpad:

2012/09/05 12:13:24 Loading data for branch bzr+ssh://bazaar.launchpad.net/+branch/juju/...
2012/09/05 12:13:40 error: Failed to load data for branch bzr+ssh://bazaar.launchpad.net/+branch/juju/: Get https://api.launchpad.net/devel/branches?ws.op=getByUrl&url=lp%3Ajuju%2F: EOF
2012/09/05 12:13:40 error: Failed to load data for branch bzr+ssh://bazaar.launchpad.net/+branch/juju/: Get https://api.launchpad.net/devel/branches?ws.op=getByUrl&url=lp%3Ajuju%2F: EOF

On the second try, it worked.

Apparently it is not uncommon or unexpected for launchpad to return a 502 on occassion, and launchpadlib has code for retrying in that case.