goprotobuf: Fix test for text format number too large for int64.

LGTM=nigeltao
R=nigeltao
CC=golang-codereviews
https://codereview.appspot.com/111460043
diff --git a/proto/text_parser.go b/proto/text_parser.go
index 4d4167c..d235ca9 100644
--- a/proto/text_parser.go
+++ b/proto/text_parser.go
@@ -612,6 +612,7 @@
 			fv.SetInt(x)
 			return nil
 		}
+
 		if len(props.Enum) == 0 {
 			break
 		}
@@ -630,6 +631,7 @@
 			fv.SetInt(x)
 			return nil
 		}
+
 	case reflect.Ptr:
 		// A basic field (indirected through pointer), or a repeated message/group
 		p.back()