Take 2 of 3c26b8f790952d4e6e14a67b127ee24998451c18
Take 2 of 3c26b8f790952d4e6e14a67b127ee24998451c18

Apparently appengine.IsTimeoutError does not return true for these errors, so
instead we need to match on the error text (always of the form
`Post <url>: Call error 11:`)

mihaip/slack-archive,mihaip/slack-archive,mihaip/slack-archive,mihaip/slack-archive