Bug 1038836 - [email/backend] Mailing list text/plain footers added (with a multipart/mixed container) to text/html parts are detected as unnamed attachments. r=asuth

land https://github.com/mozilla-b2g/gaia-email-libs-and-more/pull/322
Merge pull request #22088 from asutherland/email-text-inline

Bug 1038836 - [email/backend] Mailing list text/plain footers added (with a multipart/mixed container) to text/html parts are detected as unnamed attachments. r=asuth