fix issue with incorrect build status environment variable

agent/agent.go

@@ -203,7 +203,7 @@ func (a *Agent) exec(spec *yaml.Config, payload *queue.Work, cancel <-chan bool)
 			}
 			// updates the build status passed into each container. I realize this is
 			// a bit out of place and will work to resolve.
-			pipeline.Head().Environment["DRONE_STATUS"] = status
+			pipeline.Head().Environment["DRONE_BUILD_STATUS"] = status
 
 			if !pipeline.Head().Constraints.Match(
 				a.Platform,