Make git-cl more accurately imitate git's editor selection process, and respect $VISUAL.

tests/save-description-on-failure.sh

 #!/bin/bash
 
 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # We should save a change's description when an upload fails.
 
 set -e
 
@@ skipping 14 matching lines @@
   cd git-git
 
   DESC="this is the description"
 
   # Create a branch and check in a file.
   git checkout -q --track -b work origin
   echo foo >> test
   git add test; git commit -q -m "$DESC"
 
   # Try to upload the change to an unresolvable hostname; git-cl should fail.
-  export EDITOR=$(which true)
+  export GIT_EDITOR=$(which true)
   git config rietveld.server bogus.example.com:80
   test_expect_failure "uploading to bogus server" "$GIT_CL upload 2>/dev/null"
 
   # Check that the change's description was saved.
   test_expect_success "description was backed up" \
     "grep -q '$DESC' '$BACKUP_FILE'"
 )
 
 SUCCESS=$?
 
 cleanup
 
 # Restore the previously-saved description.
 rm -f "$BACKUP_FILE"
 if [ -e "$BACKUP_FILE_TMP" ]; then
   mv "$BACKUP_FILE_TMP" "$BACKUP_FILE"
 fi
 
 if [ $SUCCESS == 0 ]; then
   echo PASS
 fi