backtrace name collision

[AndyGauge]

https://travis-ci.com/rust-lang-nursery/error-chain/jobs/240939141#L293

error: a method with this name may be added to the standard library in the future

--> src/lib.rs:657:41

|

657 | if let Some(backtrace) = self.0.backtrace() {

|                                         ^^^^^^^^^

|

= note: `-D unstable-name-collisions` implied by `-D warnings`

= warning: once this method is added to the standard library, the ambiguity may cause an error or change in behavior!

= note: for more information, see issue #48919 <https://github.com/rust-lang/rust/issues/48919>

= help: call with fully qualified syntax `ChainedError::backtrace(...)` to keep using the current method

= help: add `#![feature(backtrace)]` to the crate attributes to enable `std::error::Error::backtrace`

[palfrey]

This should be fixed by #279