lnwire: shift fields in NodeAnnouncment to match recent BOLT-0007 changes

This commit modifies the NodeAnnouncement message to ensure that it
matches the current spec ordering. The spec was recently modified to
place the feature vector first to allow for future changes to the
fields to be forwards compatible.

lnwire/lnwire_test.go

@@ -384,14 +384,14 @@ func TestLightningWireProtocol(t *testing.T) {
 
 			req := NodeAnnouncement{
 				Signature: testSig,
+				Features:  randFeatureVector(r),
 				Timestamp: uint32(r.Int31()),
-				Alias:     newAlias(a[:]),
+				Alias:     a,
 				RGBColor: RGB{
 					red:   uint8(r.Int31()),
 					green: uint8(r.Int31()),
 					blue:  uint8(r.Int31()),
 				},
-				Features:  randFeatureVector(r),
 				Addresses: testAddrs,
 			}
 			req.Features.featuresMap = nil