Update .travis.yml

Author: Aragas

.travis.yml

@@ -20,7 +20,7 @@ script:
   - dotnet restore src/PCLExt.FileStorage.NetFX
   - dotnet restore test/PCLExt.FileStorage.Core.Test
   - dotnet restore test/PCLExt.FileStorage.NetFX.Test
-  - dotnet build src/PCLExt.FileStorage.Standard.Abstractions
+  - dotnet build src/PCLExt.FileStorage.Abstractions
   - dotnet build src/PCLExt.FileStorage.Core
   - FrameworkPathOverride=$MONO_BASE_PATH/4.5-api/ dotnet build src/PCLExt.FileStorage.NetFX
   - dotnet build test/PCLExt.FileStorage.Core.Test