don't obfuscate error during create

Signed-off-by: Brian Goff <cpuguy83@gmail.com>

daemon/create.go

@@ -20,7 +20,6 @@ import (
 	"github.com/docker/docker/pkg/idtools"
 	"github.com/docker/docker/pkg/stringid"
 	"github.com/docker/docker/runconfig"
-	volumestore "github.com/docker/docker/volume/store"
 	"github.com/opencontainers/runc/libcontainer/label"
 )
 
@@ -242,9 +241,6 @@ func (daemon *Daemon) VolumeCreate(name, driverName string, opts, labels map[str
 
 	v, err := daemon.volumes.Create(name, driverName, opts, labels)
 	if err != nil {
-		if volumestore.IsNameConflict(err) {
-			return nil, fmt.Errorf("A volume named %s already exists. Choose a different volume name.", name)
-		}
 		return nil, err
 	}
 

integration-cli/docker_cli_external_volume_driver_unix_test.go

@@ -287,7 +287,7 @@ func (s *DockerExternalVolumeSuite) TestVolumeCLICreateOptionConflict(c *check.C
 
 	out, _, err := dockerCmdWithError("volume", "create", "test", "--driver", volumePluginName)
 	c.Assert(err, check.NotNil, check.Commentf("volume create exception name already in use with another driver"))
-	c.Assert(out, checker.Contains, "A volume named test already exists")
+	c.Assert(out, checker.Contains, "must be unique")
 
 	out, _ = dockerCmd(c, "volume", "inspect", "--format={{ .Driver }}", "test")
 	_, _, err = dockerCmdWithError("volume", "create", "test", "--driver", strings.TrimSpace(out))
@@ -570,7 +570,7 @@ func (s *DockerExternalVolumeSuite) TestExternalVolumeDriverOutOfBandDelete(c *c
 
 	out, err = s.d.Cmd("volume", "create", "-d", "local", "--name", "test")
 	c.Assert(err, checker.NotNil, check.Commentf(out))
-	c.Assert(out, checker.Contains, "volume named test already exists")
+	c.Assert(out, checker.Contains, "must be unique")
 
 	// simulate out of band volume deletion on plugin level
 	delete(p.vols, "test")