dns/dsc Update to 2.7.0 and add rc.d script

[leres]

Summary

Proposed commit message:

Update to 2.7.0. Add --with-extra-cflags=-I${PREFIX}/include
so configure finds pcap/sll.h. Add a rc.d script. Fix the
path to the config directory in upload-prep.pl or else it
silently exits without doing anything when it doesn't find
any configs.

PR:		230661
Reviewed by:	? (mentor)
Approved by:	Leo Vandewoestijn (maintainer), ? (mentor)
Differential Revision:	?

[ler]

LGTM