pgcrypto: Code cleanup for decrypt_internal.

Remove some unnecessary null-tests, and replace a goto-label construct
with an "if" block.

Michael Paquier, reviewed by me.

contrib/pgcrypto/pgp-pgsql.c

@@ -575,34 +575,24 @@ decrypt_internal(int is_pubenc, int need_text, text *data,
 		err = pgp_set_symkey(ctx, (uint8 *) VARDATA(key),
 							 VARSIZE(key) - VARHDRSZ);
 
-	/*
-	 * decrypt
-	 */
+	/* decrypt */
 	if (err >= 0)
+	{
 		err = pgp_decrypt(ctx, src, dst);
 
-	/*
-	 * failed?
-	 */
-	if (err < 0)
-		goto out;
-
 		if (ex.expect)
 			check_expect(ctx, &ex);
 
 		/* remember the setting */
 		got_unicode = pgp_get_unicode_mode(ctx);
+	}
 
-out:
-	if (src)
 	mbuf_free(src);
-	if (ctx)
 	pgp_free(ctx);
 
 	if (err)
 	{
 		px_set_debug_handler(NULL);
-		if (dst)
 		mbuf_free(dst);
 		ereport(ERROR,
 				(errcode(ERRCODE_EXTERNAL_ROUTINE_INVOCATION_EXCEPTION),