To assist with troubleshooting, have added a DEBUG macro for
logging messages to the named logger roscpp_internal.connections.
We need more connection leve diagnostics in our logs but turning
on DEBUG for roscpp_internal generates a flood of information. We
only need visibility into when tcpros connections are created/dropped
for publishers and subscribers. The roscpp_internal.connections
targets those specific messages while still inheriting the log level
for roscpp_internal.