Fix a bug that allowed duplicate module names.

Change-Id: I9317e43ac435a26397557328036c11a8a2da7480
diff --git a/blueprint/context.go b/blueprint/context.go
index e9fa84b..2340fc0 100644
--- a/blueprint/context.go
+++ b/blueprint/context.go
@@ -588,7 +588,7 @@
 			Err: fmt.Errorf("<-- previous definition here"),
 			Pos: c.moduleInfo[first].pos,
 		})
-		if len(errs) >= maxErrors {
+		if len(errs) > 0 {
 			return errs
 		}
 	}