Remove duplicate variable declaration in fe-connect.c

The same variables are declared twice when checking if a connection is
writable, which is useless.

Author: Haribabu Kommi
Discussion: https://postgr.es/m/CAJrrPGf=rcALB54w_Tg1_hx3y+cgSWaERY-uYSQzGc3Zt5XN4g@mail.gmail.com

src/interfaces/libpq/fe-connect.c

@@ -3349,9 +3349,6 @@ keep_going:						/* We will come back to here until there is
 					if (strncmp(val, "on", 2) == 0)
 					{
 						/* Not writable; fail this connection. */
-						const char *displayed_host;
-						const char *displayed_port;
-
 						PQclear(res);
 						restoreErrorMessage(conn, &savedMessage);