Log Message:
mk/bsd.pkg.install.mk now automatically registers
the RCD_SCRIPTS rc.d script(s) to the PLIST.

This GENERATE_PLIST idea is part of Greg A. Woods'
PR #22954.

This helps when the RC_SCRIPTS are installed to
a different ${RCD_SCRIPTS_EXAMPLEDIR}. (Later,
the default RCD_SCRIPTS_EXAMPLEDIR will be changed
to be more clear that they are the examples.)

These patches also remove the etc/rc.d/ scripts from PLISTs
(of packages that use RCD_SCRIPTS). (This also removes
now unused references from openssh* makefiles. Note that
qmail package has not been changed yet.)

I have been doing automatic PLIST registration for RC_SCRIPTS
for over a year. Not all of these packages have been tested,
but many have been tested and used.

Somethings maybe to do:
- a few packages still manually install the rc.d scripts to
  hard-coded etc/rc.d. These need to be fixed.
- maybe  remove from mk/${OPSYS}.pkg.dist mtree specifications too.