Changelog: Update issue number

Author: lasseebert

CHANGELOG.md

@@ -21,7 +21,7 @@
 * [#1001](https://github.com/intridea/grape/pull/1001): Fixed calling endpoint with specified format with format in its path - [@hodak](https://github.com/hodak).
 * [#1005](https://github.com/intridea/grape/pull/1005): Fixed the Grape::Middleware::Globals - [@urkle](https://github.com/urkle).
 * [#1012](https://github.com/intridea/grape/pull/1012): Fixed `allow_blank: false` with a Boolean value of `false` - [@mfunaro](https://github.com/mfunaro).
-* [#XXX](https://github.com/intridea/grape/pull/XXX): Fixed `undefined method stringify_keys` with nested mutual exclusive params - [@quickpay](https://github.com/quickpay).
+* [#1017](https://github.com/intridea/grape/pull/1017): Fixed `undefined method stringify_keys` with nested mutual exclusive params - [@quickpay](https://github.com/quickpay).
 * Your contribution here.
 
 0.11.0 (2/23/2015)