API: Properly quote name

RFC 5322, "Internet Message Format" specifies in §3.4 Address
Specification that commas separate the addresses in a list. But some
people use comma in their name:

    pwclient list -S "$series_id" -f '%{submitter}'
    Surname, Name <foo@example.com>

Using passing the output to git send-email causes it to fail (at least
dovecot refuses to send):

    git send-email --to="Surname, Name <foo@example.com>" ...
    5.5.4 Invalid TO: Missing domain

Quoting name helps:

    pwclient list -S "$series_id" -f '%{submitter}'
    "Surname, Name" <foo@example.com>

    git send-email --to='"Surname, Name" <foo@example.com>" ...
    To: "Surname, Name" <foo@example.com>
    Result: 250

Signed-off-by: Petr Vorel <pvorel@suse.cz>

Author: pevik

pwclient/api.py

@@ -752,7 +752,11 @@ def _format_person(person):
                 return ''
 
             if person['name']:
-                return f"{person['name']} <{person['email']}>"
+                name = person['name']
+                # quoting names with comma (unless already quoted)
+                if ',' in name and not '"' in name:
+                    name = f'"{name}"'
+                return f"{name} <{person['email']}>"
             return person['email']
 
         def _format_user(user):