Use a different env variable for appveyor api key

The actual appveyor build had the previous environment variable already defined, so use a different name for the one used in tests.

Author: Redth

src/Cake.AppVeyor.Tests/Keys.cs

@@ -1,14 +1,14 @@
-using System;
+using System;
 using System.IO;
 
-namespace Cake.AppVeyor.Tests
-{
-    public static class Keys
-    {
-        const string YOUR_APPVEYOR_API_TOKEN = "{APPVEYOR_APITOKEN}";
-
-        static string appVeyorApiToken;
-
+namespace Cake.AppVeyor.Tests
+{
+    public static class Keys
+    {
+        const string YOUR_APPVEYOR_API_TOKEN = "{APPVEYOR_APITOKEN}";
+
+        static string appVeyorApiToken;
+
         public static string AppVeyorApiToken {
             get
             {
@@ -21,7 +21,7 @@ public static string AppVeyorApiToken {
 
                     // Next check for an environment variable
                     if (string.IsNullOrEmpty(appVeyorApiToken))
-                        appVeyorApiToken = Environment.GetEnvironmentVariable("appveyor_api_token");
+                        appVeyorApiToken = Environment.GetEnvironmentVariable("test_appveyor_api_token");
 
                     // Finally use the const value
                     if (string.IsNullOrEmpty(appVeyorApiToken))
@@ -30,7 +30,7 @@ public static string AppVeyorApiToken {
 
                 return appVeyorApiToken;
             }
-        }
-    }
-}
-
+        }
+    }
+}
+