git-send-email: do not double-escape quotes from mutt

git-send-email: do not double-escape quotes from mutt

mutt saves aliases with escaped quotes in the form of:

	alias dot \"Dot U. Sir\" <redacted>

When we pass through our sanitize_address routine,
we end up with double-escaping:

	 To: "\\\"Dot U. Sir\\\" <redacted>

Remove the escaping in mutt only for now, as I am not sure
if other mailers can do this or if this is better fixed in
sanitize_address.

Cc: Remi Lespinet <redacted>
Cc: Matthieu Moy <redacted>
Signed-off-by: Eric Wong <redacted>
Signed-off-by: Junio C Hamano <redacted>