Bug 860262 - [Email] When selecting the option “replying to all” or “reply” or “forward” on an email that was previously sent without Subject, the new Subject is shown as: “Re:null” or “Fwd:null”
Merge pull request #10413 from mozshiao9/master_email_860262

Bug 860262 - [Email] When selecting the option “replying to all” or “reply” or “forward” on an email that was previously sent without Subject, the new Subject is shown as: “Re:null” or “Fwd:null”, r=asutherland