acme: let Edit redo when file is clean

R=, rsc
CC=
http://codereview.appspot.com/188042

src/cmd/acme/ecmd.c

diff --git a/src/cmd/acme/ecmd.c b/src/cmd/acme/ecmd.c
index 575c5a2..bdcaf9f 100644
--- a/src/cmd/acme/ecmd.c
+++ b/src/cmd/acme/ecmd.c
@@ -544,7 +544,7 @@
 		flag = FALSE;
 	}
 	oseq = -1;
-	while(n-->0 && t->file->seq!=0 && t->file->seq!=oseq){
+	while(n-->0 && t->file->seq!=oseq){
 		oseq = t->file->seq;
 		undo(t, nil, nil, flag, 0, nil, 0);
 	}