remove duplicate sentence (#1559)

Author: krancour

CONTRIBUTING.md

@@ -7,7 +7,7 @@ The Microsoft acs-engine project accepts contributions via GitHub pull requests.
 We'd love to accept your patches! Before we can take them, we have to jump a
 couple of legal hurdles.
 
-The [Microsoft CLA](https://cla.microsoft.com/) must be signed by all contributors. Please fill out either the individual or corporate Contributor License Agreement (CLA). Once you are CLA'ed, we'll be able to accept your pull requests. Once you are CLA'ed, we'll be able to accept your pull requests.
+The [Microsoft CLA](https://cla.microsoft.com/) must be signed by all contributors. Please fill out either the individual or corporate Contributor License Agreement (CLA). Once you are CLA'ed, we'll be able to accept your pull requests.
 
 ***NOTE***: Only original source code from you and other people that have
 signed the CLA can be accepted into the repository.