delete/rewrite calls to panicln

R=rsc
CC=golang-dev
http://codereview.appspot.com/745041

compiler/main.go

@@ -458,7 +458,6 @@ func (g *Generator) BuildTypeNameMap() {
 func (g *Generator) objectNamed(typeName string) Object {
 	f, ok := g.typeNameToObject[typeName]
 	if !ok {
-panicln()
 		g.fail("can't find object with type", typeName)
 	}
 	return f

proto/properties.go

@@ -508,7 +508,7 @@ var enumValueMaps = make(map[string]map[string]int32)
 // maps into the global table to aid parsing ASCII protocol buffers.
 func RegisterEnum(typeName string, nameMap map[int32]string, valueMap map[string]int32) {
 	if _, ok := enumNameMaps[typeName]; ok {
-		panicln("proto: duplicate enum registered: ", typeName)
+		panic("proto: duplicate enum registered: " + typeName)
 	}
 	enumNameMaps[typeName] = nameMap
 	enumValueMaps[typeName] = valueMap