Bug 876622 - [email/IMAP] snippet fetching logic does not handle connection loss correctly. r=squib

land https://github.com/mozilla-b2g/gaia-email-libs-and-more/pull/207
Merge pull request #10058 from asutherland/email-offline-during-body

Bug 876622 - [email/IMAP] snippet fetching logic does not handle connection loss correctly. r=squib