Fix code for splitting KEY=VALUE env vars

Make the code work with env values with "=" in them as well as entries of the
form "KEY" (no "=")

docker-gen.go

@@ -100,8 +100,11 @@ type Context []*RuntimeContainer
 func (c *Context) Env() map[string]string {
 
 	env := make(map[string]string)
-	for _, i := range os.Environ() {
-		parts := strings.Split(i, "=")
+	for _, entry := range os.Environ() {
+		parts := strings.SplitN(entry, "=", 2)
+		if len(parts) != 2 {
+			parts = append(parts, "")
+		}
 		env[parts[0]] = parts[1]
 	}
 	return env

docker_client.go

@@ -148,7 +148,10 @@ func getContainers(client *docker.Client) ([]*RuntimeContainer, error) {
 		}
 
 		for _, entry := range container.Config.Env {
-			parts := strings.Split(entry, "=")
+			parts := strings.SplitN(entry, "=", 2)
+			if len(parts) != 2 {
+				parts = append(parts, "")
+			}
 			runtimeContainer.Env[parts[0]] = parts[1]
 		}