all: upgrade farmer.golang.org links to https

Since farmer.golang.org has a valid certificate in production now, we
should use that certificate for retrieving data.

Change-Id: I3685d84953ea11e6ac09b4692fa27c73538a565c
Reviewed-on: https://go-review.googlesource.com/39290
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/types/types.go b/types/types.go
index 548ba9b..f64bbbf 100644
--- a/types/types.go
+++ b/types/types.go
@@ -126,7 +126,7 @@
 	Machines map[string]*ReverseBuilder
 }
 
-// ReverseBuilderStatus is http://farmer.golang.org/status/reverse.json
+// ReverseBuilderStatus is https://farmer.golang.org/status/reverse.json
 //
 // It is used by monitoring and the Mac VMWare infrastructure to
 // adjust the Mac VMs based on deaths and demand.