Fix new golint reported errors

Signed-off-by: Alessandro Boch <aboch@docker.com>

libnetwork/client/client.go

@@ -65,7 +65,7 @@ func (cli *NetworkCli) Cmd(chain string, args ...string) error {
 	if len(args) > 0 {
 		method, exists := cli.getMethod(args[0])
 		if !exists {
-			return fmt.Errorf("%s: '%s' is not a %s command. See '%s --help'.\n", chain, args[0], chain, chain)
+			return fmt.Errorf("%s: '%s' is not a %s command. See '%s --help'", chain, args[0], chain, chain)
 		}
 		return method(chain, args[1:]...)
 	}

libnetwork/cmd/dnet/dnet.go

@@ -247,7 +247,7 @@ type NetworkOrchestration struct {
 
 func (d *dnetConnection) dnetDaemon(cfgFile string) error {
 	if err := startTestDriver(); err != nil {
-		return fmt.Errorf("failed to start test driver: %v\n", err)
+		return fmt.Errorf("failed to start test driver: %v", err)
 	}
 
 	cfg, err := d.parseConfig(cfgFile)

libnetwork/drivers/overlay/ov_endpoint.go

@@ -77,7 +77,7 @@ func (d *driver) CreateEndpoint(nid, eid string, ifInfo driverapi.InterfaceInfo,
 	}
 
 	if s := n.getSubnetforIP(ep.addr); s == nil {
-		return fmt.Errorf("no matching subnet for IP %q in network %q\n", ep.addr, nid)
+		return fmt.Errorf("no matching subnet for IP %q in network %q", ep.addr, nid)
 	}
 
 	if ep.mac == nil {

libnetwork/drivers/overlay/peerdb.go

@@ -277,7 +277,7 @@ func (d *driver) peerAdd(nid, eid string, peerIP net.IP, peerIPMask net.IPMask,
 
 	s := n.getSubnetforIP(IP)
 	if s == nil {
-		return fmt.Errorf("couldn't find the subnet %q in network %q\n", IP.String(), n.id)
+		return fmt.Errorf("couldn't find the subnet %q in network %q", IP.String(), n.id)
 	}
 
 	if err := n.obtainVxlanID(s); err != nil {

libnetwork/drivers/solaris/overlay/ov_endpoint.go

@@ -76,7 +76,7 @@ func (d *driver) CreateEndpoint(nid, eid string, ifInfo driverapi.InterfaceInfo,
 	}
 
 	if s := n.getSubnetforIP(ep.addr); s == nil {
-		return fmt.Errorf("no matching subnet for IP %q in network %q\n", ep.addr, nid)
+		return fmt.Errorf("no matching subnet for IP %q in network %q", ep.addr, nid)
 	}
 
 	if ep.mac == nil {

libnetwork/drivers/solaris/overlay/peerdb.go

@@ -263,7 +263,7 @@ func (d *driver) peerAdd(nid, eid string, peerIP net.IP, peerIPMask net.IPMask,
 
 	s := n.getSubnetforIP(IP)
 	if s == nil {
-		return fmt.Errorf("couldn't find the subnet %q in network %q\n", IP.String(), n.id)
+		return fmt.Errorf("couldn't find the subnet %q in network %q", IP.String(), n.id)
 	}
 
 	if err := n.obtainVxlanID(s); err != nil {

libnetwork/iptables/iptables.go

@@ -130,7 +130,7 @@ func NewChain(name string, table Table, hairpinMode bool) (*ChainInfo, error) {
 // ProgramChain is used to add rules to a chain
 func ProgramChain(c *ChainInfo, bridgeName string, hairpinMode, enable bool) error {
 	if c.Name == "" {
-		return fmt.Errorf("Could not program chain, missing chain name.")
+		return fmt.Errorf("Could not program chain, missing chain name")
 	}
 
 	switch c.Table {
@@ -166,7 +166,7 @@ func ProgramChain(c *ChainInfo, bridgeName string, hairpinMode, enable bool) err
 		}
 	case Filter:
 		if bridgeName == "" {
-			return fmt.Errorf("Could not program chain %s/%s, missing bridge name.",
+			return fmt.Errorf("Could not program chain %s/%s, missing bridge name",
 				c.Table, c.Name)
 		}
 		link := []string{