Build failure with backtrace 0.3.10

[mpapierski]

Hello,

Today backtrace crate got 0.3.10 release and apparently it introduces a regression - I can't build failure v0.1.3 anymore in my crate because cargo resolved backtrace to 0.3.10. See rust-lang/backtrace-rs#134 for more details.

I'm not yet sure if its a planned regression and failure needs to be updated to accomodate changes (probably more crates can be affected by that).

[BurntSushi]

See #279, #280

[mpapierski]

@BurntSushi Thanks! That was fast. I'm open for closing this one, but I'd keep it for a while for better visibility for awhile.

[mitsuhiko]

Closing this as master would be compatible with this.