google-api-go-client: Fix broken return types for resumable uploads of other APIs.

Change-Id: I687b7777b1cc87f09cd4e6581bf43abc001ea719
Reviewed-on: https://code-review.googlesource.com/1850
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

google-api-go-generator/gen.go

diff --git a/google-api-go-generator/gen.go b/google-api-go-generator/gen.go
index 45d2cd4..a720f00 100644
--- a/google-api-go-generator/gen.go
+++ b/google-api-go-generator/gen.go
@@ -1353,7 +1353,7 @@
 		pn(` req.Header.Set("X-Upload-Content-Type", c.mediaType_)`)
 		pn(" req.Body = nil")
 		pn(` if params.Get("name") == "" {`)
-		pn(`  return nil, fmt.Errorf("resumable uploads must set the Name parameter.")`)
+		pn(`  return %sfmt.Errorf("resumable uploads must set the Name parameter.")`, nilRet)
 		pn(" }")
 		pn("} else {")
 		pn(" contentLength_, hasMedia_ := googleapi.ConditionallyIncludeMedia(c.media_, &body, &ctype)")
@@ -1382,9 +1382,7 @@
 		pn("  Callback:      progressUpdater_,")
 		pn(" }")
 		pn(" res, err = rx.Upload(c.ctx_)")
-		pn(" if err != nil {")
-		pn("  return nil, err")
-		pn(" }")
+		pn(" if err != nil { return %serr }", nilRet)
 		pn("}")
 	}
 	if retTypeComma == "" {