This patch will add the IP and port, or socket name, to the error message and
thus simplify the problem debugging: no need to check for this information in
the Nagios configuration.
This function is only used by 'check_tcp.c'.

Without the patch:

$ ./plugins/check_tcp -H 127.0.0.1 -p 21
Connection refused
$ ./plugins/check_tcp -H /var/spool/nagios/cmd/nagios.cmd
Permission denied

With the patch:

$ ./plugins/check_tcp -H 127.0.0.1 -p 21
connect to address 127.0.0.1 and port 21: Connection refused
$ ./plugins/check_tcp -H /var/spool/nagios/cmd/nagios.cmd
connect to socket /var/spool/nagios/cmd/nagios.cmd: Permission denied

Thanks to Davide Madrisan.
---
Closes  #1277
netutils.c - A few more changes

Changed bool to short.

Removed first instance of is_socket to avoid
redeclaration error.

Changed 'socket' to 'file socket' for verbosity.