Remove an unused variable

GCC 16 warned with -Wall option:

    whois.c: In function ‘query_verisign’:
    whois.c:1043:9: warning: unused variable ‘sock’ [-Wunused-variable]
     1043 |     int sock;
	  |         ^~~~

This patch removes the unused variable.

whois.c

@@ -1040,7 +1040,6 @@ char *query_server(const char *server, const char *port, const char *query)
 char *query_verisign(const char *server, const char *port, const char *query)
 {
     char *temp, *p;
-    int sock;
     char *referral_server = NULL;
     int dotscount = 0;