Add redhat mapping from tftpd-hpa to tftp-server

This will be needed by a patch I'll be submitting to t-e-i to
change the tftp implementation used by ubuntu, so that both
Ubuntu and Fedora can use the same implementation.

Change-Id: Ie9581265dfa2c37342e01162fe580b1948dd3e03
Merge "Add redhat mapping from tftpd-hpa to tftp-server"