send-email: lazy-load Email::Valid and make it optional
send-email: lazy-load Email::Valid and make it optional

It's not installed on enough machines, and is overkill most of
the time.  We'll fallback to a very basic regexp just in case,
but nothing like the monster regexp Email::Valid has to offer :)

Small cleanup from Merlyn.

Signed-off-by: Eric Wong <8c2951295f8292b0c03727bc4652981172298eae@yhbt.net>
Signed-off-by: Junio C Hamano <dc50d1021234060e53ec42a77d526afa2fe07479@cox.net>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git