remote-bzr, remote-hg: fix email address regular expression

remote-bzr, remote-hg: fix email address regular expression

Before, strings like "foo.bar@example.com" would be converted to
"foo. <bar@example.com>" when they should be "unknown
<foo.bar@example.com>".

Signed-off-by: Richard Hansen <rhansen@bbn.com>
Reviewed-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>