Bug 991490 - [email/backend] persistent test failure in test_compose_blobs.js due to undefined/null inconsistency in smtp/account.js. r=mcav

land https://github.com/mozilla-b2g/gaia-email-libs-and-more/pull/298
Merge pull request #18017 from asutherland/email-fix-compose-blobs-test

Bug 991490 - [email/backend] persistent test failure in test_compose_blobs.js due to undefined/null inconsistency in smtp/account.js. r=mcav