Bug 860605 - [Email/IMAP] Initial synchronization is too conservative on time windows, especially when the folder has a small number of messages. rs=squib

land https://github.com/mozilla-b2g/gaia-email-libs-and-more/pull/215
Merge pull request #10143 from asutherland/email-faster-deepening

Bug 860605 - [Email/IMAP] Initial synchronization is too conservative on time windows, especially when the folder has a small number of messages. rs=squib