Fixes GitTools#1278 - ContinuaCI use environment variable not registry.

Author: dazinator

src/GitVersionCore/BuildServers/ContinuaCi.cs

@@ -1,25 +1,16 @@
 namespace GitVersion
 {
-#if NETDESKTOP
-    using Microsoft.Win32;
+    using System;
 
     public class ContinuaCi : BuildServerBase
     {
-        public override bool CanApplyToCurrentContext()
-        {
-            const string KeyName = @"Software\VSoft Technologies\Continua CI Agent";
 
-            if (RegistryKeyExists(KeyName, RegistryView.Registry32))
-            {
-                return true;
-            }
+        public const string EnvironmentVariableName = "ContinuaCI.Version";
 
-            if (RegistryKeyExists(KeyName, RegistryView.Registry64))
-            {
-                return true;
-            }
+        public override bool CanApplyToCurrentContext()
+        {
+            return !string.IsNullOrEmpty(Environment.GetEnvironmentVariable(EnvironmentVariableName));
 
-            return false;
         }
 
         public override string[] GenerateSetParameterMessage(string name, string value)
@@ -33,17 +24,6 @@ public override string[] GenerateSetParameterMessage(string name, string value)
         public override string GenerateSetVersionMessage(VersionVariables variables)
         {
             return string.Format("@@continua[setBuildVersion value='{0}']", variables.FullSemVer);
-        }
-
-        static bool RegistryKeyExists(string keyName, RegistryView registryView)
-        {
-            var localKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, registryView);
-            localKey = localKey.OpenSubKey(keyName);
-
-            return localKey != null;
-        }
+        }    
     }
-
-#endif
-
 }