codereview: print gofmt message when aborting

R=r
CC=vish
http://go/go-review/1026013
diff --git a/lib/codereview/codereview.py b/lib/codereview/codereview.py
index a169157..2cd3018 100644
--- a/lib/codereview/codereview.py
+++ b/lib/codereview/codereview.py
@@ -594,11 +594,11 @@
 		ui.warn("gofmt errors:\n" + errors.rstrip() + "\n")
 		return
 	if len(data) > 0:
-		msg = "gofmt needs to format these files (run hg gofmt):\n" + data
+		msg = "gofmt needs to format these files (run hg gofmt):\n" + Indent(data, "\t").rstrip()
 		if just_warn:
-			ui.warn("warning: " + msg)
+			ui.warn("warning: " + msg + "\n")
 		else:
-			raise util.Abort()
+			raise util.Abort(msg)
 	return
 
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