zed: fix sending emails

Commit 6fc3099 broke the quoting when invoking the mail program, revert part of that change

Author: lnicola

cmd/zed/zed.d/zed-functions.sh

@@ -267,7 +267,7 @@ zed_notify_email()
                 -e "s/@SUBJECT@/${subject}/g")"
 
     # shellcheck disable=SC2086
-    ${ZED_EMAIL_PROG} ${ZED_EMAIL_OPTS} < "${pathname}" >/dev/null 2>&1
+    eval "${ZED_EMAIL_PROG}" ${ZED_EMAIL_OPTS} < "${pathname}" >/dev/null 2>&1
     rv=$?
     if [ "${rv}" -ne 0 ]; then
         zed_log_err "$(basename "${ZED_EMAIL_PROG}") exit=${rv}"