build: apply DFLT_NAME/profiles in init script

build: apply DFLT_NAME/profiles in init script

Hopefully at some point we can get rid of the --enable-datacenter switch
and just have the init script do magic.  Should already work for Cumulus
as it is.

NB: the profile name can't be baked into the package.  The whole point
is to make the package profile-agnostic;  in theory at some point the
exact same package files should work on both, say, a Cumulus switch and
a Linux software BGP DFZ router.

Signed-off-by: David Lamparter <equinox@diac24.net>