[x/blog] content: fix broken link in blog.golang.org/error-handling-and-go
[x/blog] content: fix broken link in blog.golang.org/error-handling-and-go

In the section about `json.SyntaxError` the link to the source of
`jsonconfig/eval.go` of the camlistore project was not correct
anymore. This change updates it to the github source view.

Change-Id: I097a423c3325acb1e6d229774757b22367e444a0
Reviewed-on: https://go-review.googlesource.com/22414
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>
X-Blog-Commit: 36426579e19aa6748484faeb9118e84826ee8531

golang/website,golang/website,golang/website,golang/website,golang/website,golang/website,golang/website