Various simplifications (gosimple)

This fixes:
clientconn.go:948:3: should write m = cc.sc.Methods[method[:i+1]] instead of m, _ = cc.sc.Methods[method[:i+1]] (S1005)
encoding/proto/proto_test.go:43:5: should use !bytes.Equal(p.GetBody(), expectedBody) instead (S1004)
resolver/dns/dns_resolver.go:260:2: should merge variable declaration with assignment on next line (S1021)
resolver/dns/dns_resolver.go:344:2: should use 'return <expr>' instead of 'if <expr> { return <bool> }; return <bool>' (S1008)

clientconn.go

@@ -945,7 +945,7 @@ func (cc *ClientConn) GetMethodConfig(method string) MethodConfig {
 	m, ok := cc.sc.Methods[method]
 	if !ok {
 		i := strings.LastIndex(method, "/")
-		m, _ = cc.sc.Methods[method[:i+1]]
+		m = cc.sc.Methods[method[:i+1]]
 	}
 	return m
 }

encoding/proto/proto_test.go

@@ -40,7 +40,7 @@ func marshalAndUnmarshal(t *testing.T, codec encoding.Codec, expectedBody []byte
 		t.Errorf("codec.Unmarshal(_) returned an error")
 	}
 
-	if bytes.Compare(p.GetBody(), expectedBody) != 0 {
+	if !bytes.Equal(p.GetBody(), expectedBody) {
 		t.Errorf("Unexpected body; got %v; want %v", p.GetBody(), expectedBody)
 	}
 }

resolver/dns/dns_resolver.go

@@ -257,8 +257,7 @@ func (d *dnsResolver) lookupHost() []resolver.Address {
 }
 
 func (d *dnsResolver) lookup() ([]resolver.Address, string) {
-	var newAddrs []resolver.Address
-	newAddrs = d.lookupSRV()
+	newAddrs := d.lookupSRV()
 	// Support fallback to non-balancer address.
 	newAddrs = append(newAddrs, d.lookupHost()...)
 	sc := d.lookupTXT()
@@ -341,10 +340,7 @@ func chosenByPercentage(a *int) bool {
 	}
 	s := rand.NewSource(time.Now().UnixNano())
 	r := rand.New(s)
-	if r.Intn(100)+1 > *a {
-		return false
-	}
-	return true
+	return r.Intn(100)+1 <= *a
 }
 
 func canaryingSC(js string) string {