talksapp: remove decoration to errors at top level
talksapp: remove decoration to errors at top level

The errors returned are used to decide what status code
should be set on the http response.

Fixes #441.

Change-Id: Ia01ed2186dd6d23cd38402888df7d2de3f687d0a
Reviewed-on: https://go-review.googlesource.com/28781
Reviewed-by: Chris Broadfoot <0c2851a4f8ab4aa5606e69c0757771dd13dbe686@golang.org>

golang/gddo,segmentio/gddo,segmentio/gddo,golang/gddo,golang/gddo,golang/gddo,segmentio/gddo,segmentio/gddo