blog: fix link to cgo source file in Cgo post.

Change-Id: Id22ff1842f85ceb312c2f5e37e6440e7e80ac727
Reviewed-on: https://go-review.googlesource.com/15690
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Andrew Gerrand <adg@golang.org>
diff --git a/content/c-go-cgo.article b/content/c-go-cgo.article
index 287d933..d0e9976 100644
--- a/content/c-go-cgo.article
+++ b/content/c-go-cgo.article
@@ -106,4 +106,4 @@
 
 For a simple, idiomatic example of a cgo-based package, see Russ Cox's [[http://code.google.com/p/gosqlite/source/browse/sqlite/sqlite.go][gosqlite]]. Also, the Go Project Dashboard lists [[https://godashboard.appspot.com/project?tag=cgo][several other cgo packages]].
 
-Finally, if you're curious as to how all this works internally, take a look at the introductory comment of the runtime package's [[http://golang.org/src/pkg/runtime/cgocall.c][cgocall.c]].
+Finally, if you're curious as to how all this works internally, take a look at the introductory comment of the runtime package's [[https://golang.org/src/runtime/cgocall.go][cgocall.go]].