contributing: typo: treshold->threshold

Fix obvious typo 'treshold' in the 'Enabling Travis' section of
the CONTRIBUTING doc.

Signed-off-by: Graham Whaley <[email protected]>

CONTRIBUTING.md

@@ -66,7 +66,7 @@ We request you give quality assurance some consideration by:
 * Using our [test-cases](https://github.com/01org/ciao/tree/master/test-cases) package to run unit tests because a simple ```gotest ./...``` can result in multiple packages' unit tests running in parallel which may be unsafe.  Simply replace ```go test``` with ```test-cases``` in your workflow.
 * Running basic cluster acceptance tests which are available in [_release/bat](https://github.com/01org/ciao/tree/master/_release/bat) and are most easily run inside a [singlevm](https://github.com/01org/ciao/tree/master/testutil/singlevm) test environment, but may also be run on a hardware cluster which has your code installed/configured/running.  In some cases it will be necessary to test on real hardware, but in many a virtual cluster is an easy and fully sufficient path to test.
 * Adding BAT tests for changes where it makes sense.  The BAT tests themselves are implemented in go in the [bat package](https://github.com/01org/ciao/tree/master/bat), which is essentially a wrapper/driver around ciao-cli.  Both the [bat package](https://github.com/01org/ciao/tree/master/bat) and [BAT tests](https://github.com/01org/ciao/tree/master/_release/bat) are easy to extend.
-* Enabling [Travis CI](https://travis-ci.org/01org/ciao) on your github fork of Ciao to get continuous integration feedback on your dev/test branches. We have tresholds on code coverage tracked by [coveralls](https://coveralls.io/github/01org/ciao) which you will see reported once you submit your pull request.
+* Enabling [Travis CI](https://travis-ci.org/01org/ciao) on your github fork of Ciao to get continuous integration feedback on your dev/test branches. We have thresholds on code coverage tracked by [coveralls](https://coveralls.io/github/01org/ciao) which you will see reported once you submit your pull request.
 
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