Prevent setting the title for e.g. screen's hardstatus by vim - as
recently implemented[1] - when editing mails. Otherwise the window
name may get very long and may screw up screen's hardstatus line. On
the other hand renaming the window to `&shell'[1] after editing the
mail is prevented.

                   ---------- Footnotes ----------

[1] http://hg.grml.org/grml-etc-core/rev/acfecae478bc