Allow multiple "important" command sockets. #3982

Not yet useful...
Track lists of socket pairs, not just one #3982
SockPair now manages de/alloc of Safe/ReliSocks. #3982

Now that the SafeSock and ReliSock for a command port are collected
inside a vector of SockPairs, it was getting a bit muzzy who owned the
memory.  Now it's SockPair, always. This will simplify teaching
DaemonCore::InitCommandSockets to return a vector of SockPairs.
InitCommandSockets can now return a list of sockets

...at least the API supports it.  It still only returns one thing, and
other code will likely break when it returns more than one thing.  But
this is a step toward returning sockets on both IPv4 and IPv6
simultaneously. #3982
Merge branch 'master' into master-ipv6-mixed-mode

Also changed some #warnings into PRAGMA_REMIND for portability.
Allow inherited command sockets to be a list.

.#3982
Merge branch 'master' into master-ipv6-mixed-mode
Reli/SafeSocks now accept proto as argument #3982

This is preperatory work for getting InitCommandSockets to bind to
multiple protocols.
Flag some functions as deprecated. #3982
ReliSock::listen(int port) now takes protocol as well. #3982
Daemoncore can now listen multi-protocol #3982

It's only going to advertise one. And no promises that it actually
works.  But it's listening now.
Func to turn condor_protocol to human readable string

useful for logs.
Now actually tries to listen on IPv6 .#3982

Missed a few cases where we need to pass the protocol down.
Better error messages when failing to bind to IPv6 #3982
Tweak some deprecation warnings.
BindAnyCommandPort sans-protocl is now local only

BindAnyCommandPort requires a protocol.  The only two users using the
old version (which doesn't require a protocol) are using it for a
local-only socket.  So rename it to BindAnyLocalCommandPort and document
it as such.
Remove spurious warning.
Add missing newlines in log messages
IPv6 socket shouldn't also grab IPv4 #3982
Ensure af_type is always set.