[mail] allow to specify SMTP's MAIL FROM address to config.sendmails(). Closes #3373620
Also modify testlib.Email so we don't loose this information and may test it.
#! /bin/sh -e
#
if [ "$1" = configure ]; then
if which install-docs >/dev/null 2>&1; then
install-docs -i /usr/share/doc-base/cubicweb-doc
fi
fi
#DEBHELPER#
exit 0