libs, daemons: changes to permit c++ compilation

libs, daemons: changes to permit c++ compilation

Some misc changes to resolve some c++ compilation errors.
The goal is only to permit an external module - a plugin,
for example - to see frr headers, not to support or encourage
contributions in c++. The changes include: avoiding use
of keywords like 'new', 'delete'; cleaning up implicit
type-casting from 'void *' in several places.

Signed-off-by: Mark Stapp <mjs@voltanet.io>