Remove pkg/errors; Update Gopkg.toml, but not GRPC because it breaks.

Gopkg.lock

@@ -137,7 +137,7 @@
     "db",
     "log"
   ]
-  revision = "26f2ab65f82cfc6873c312e8030104c47c05f10e"
+  revision = "9b9a9e7f8c73f6d0ae8672438a271f32060eebcb"
 
 [[projects]]
   name = "golang.org/x/net"
@@ -204,6 +204,6 @@
 [solve-meta]
   analyzer-name = "dep"
   analyzer-version = 1
-  inputs-digest = "dfad1992e9c7f0df42ab62cadb7e984f5a945904400d844ae374b76d4b07f83e"
+  inputs-digest = "b334fca7ad79cda7d2248f0f67cc342dd3faa6125d44ba3a6936edb7140d1ef4"
   solver-name = "gps-cdcl"
   solver-version = 1

Gopkg.toml

@@ -29,10 +29,6 @@
   name = "github.com/gogo/protobuf"
   version = "1.0.0"
 
-[[constraint]]
-  name = "github.com/pkg/errors"
-  version = "0.8.0"
-
 [[constraint]]
   name = "github.com/spf13/cobra"
   version = "0.0.1"

client/grpc_client.go

@@ -6,7 +6,6 @@ import (
 	"sync"
 	"time"
 
-	"github.com/pkg/errors"
 	context "golang.org/x/net/context"
 	grpc "google.golang.org/grpc"
 
@@ -105,7 +104,7 @@ func (cli *grpcClient) StopForError(err error) {
 func (cli *grpcClient) Error() error {
 	cli.mtx.Lock()
 	defer cli.mtx.Unlock()
-	return errors.Wrap(cli.err, "grpc client error")
+	return cli.err
 }
 
 // Set listener for all responses

client/socket_client.go

@@ -3,13 +3,13 @@ package abcicli
 import (
 	"bufio"
 	"container/list"
+	"errors"
 	"fmt"
 	"net"
 	"reflect"
 	"sync"
 	"time"
 
-	"github.com/pkg/errors"
 	"github.com/tendermint/abci/types"
 	cmn "github.com/tendermint/tmlibs/common"
 )
@@ -111,7 +111,7 @@ func (cli *socketClient) StopForError(err error) {
 func (cli *socketClient) Error() error {
 	cli.mtx.Lock()
 	defer cli.mtx.Unlock()
-	return errors.Wrap(cli.err, "socket client error")
+	return cli.err
 }
 
 // Set listener for all responses