Silence warning about uninitialized 'ret' variable on some compilers.

If the compiler doesn't notice that the switch-statement handles all
possible values of the enum, it might complain that 'ret' is being used
without initialization. Jeff Janes reported that on gcc 4.4.7.

Discussion: https://www.postgresql.org/message-id/CAMkU=1x31RvP+cpooFbmc8K8nt-gNO8woGFhXcgQYYZ5ozYpFA@mail.gmail.com

src/interfaces/libpq/fe-connect.c

@@ -1668,6 +1668,7 @@ connectDBStart(PGconn *conn)
 		snprintf(portstr, sizeof(portstr), "%d", thisport);
 
 		/* Use pg_getaddrinfo_all() to resolve the address */
+		ret = 1;
 		switch (ch->type)
 		{
 			case CHT_HOST_NAME: