Use the dotnet-release package feed for Travis.
See https://github.com/dotnet/core/issues/227 for background.
diff --git a/tests.sh b/tests.sh
index ed90141..80b4abc 100755
--- a/tests.sh
+++ b/tests.sh
@@ -63,7 +63,7 @@
sudo apt-get install -qq mono-devel referenceassemblies-pcl nunit
# Then install the dotnet SDK as per Ubuntu 14.04 instructions on dot.net.
- sudo sh -c 'echo "deb [arch=amd64] https://apt-mo.trafficmanager.net/repos/dotnet/ trusty main" > /etc/apt/sources.list.d/dotnetdev.list'
+ sudo sh -c 'echo "deb [arch=amd64] https://apt-mo.trafficmanager.net/repos/dotnet-release/ trusty main" > /etc/apt/sources.list.d/dotnetdev.list'
sudo apt-key adv --keyserver apt-mo.trafficmanager.net --recv-keys 417A0893
sudo apt-get update -qq
sudo apt-get install -qq dotnet-dev-1.0.0-preview2-003121