tests: histedit-helpers fixbundle should not complain about no input

tests/histedit-helpers.sh

@@ -2,5 +2,6 b' fixbundle() {'
     grep -v 'saving bundle' | grep -v 'saved backup' | \
         grep -v added | grep -v adding | \
         grep -v "unable to find 'e' for patching" | \
-        grep -v "e: No such file or directory"
+        grep -v "e: No such file or directory" | \
+    cat
 }

tests/test-histedit-no-change.t

@@ -187,7 +187,6 b' abort editing session, after first forci'
   hist:   2 remaining (histedit --continue)
 
   $ hg histedit --abort 2>&1 | fixbundle
-  [1]
 
 modified files should survive the abort when we've moved away already
   $ hg st