cf-socket: Fix build when not HAVE_GETPEERNAME

[ryandesign]

Remove remaining references to conn and sockfd, which were removed from the function signature when conninfo_remote was renamed to conn_set_primary_ip in 6a8d7ef.

See #10213

Fixes this build failure when building for Classic Mac OS (using a new Makefile I haven't contributed yet):

### MWC68K Compiler Error:
#	(void)conn;
#	      ^^^^
# undefined identifier 'conn'
#----------------------------------------------------------
File "cf-socket.c"; Line 1177
#----------------------------------------------------------
### MWC68K Compiler Error:
#	(void)sockfd;
#	      ^^^^^^
# undefined identifier 'sockfd'
#----------------------------------------------------------
File "cf-socket.c"; Line 1178
#----------------------------------------------------------

[jay]

Thanks