issue_warnings() has no business freeing its parameter, especially not when

its sole caller does that too.  Jan Matousek, via Pavel Stehule

contrib/pg_upgrade/check.c

@@ -154,7 +154,6 @@ issue_warnings(migratorContext *ctx, char *sequence_script_file_name)
 					  ctx->new.bindir, ctx->new.port, sequence_script_file_name,
 					  ctx->logfile);
 			unlink(sequence_script_file_name);
-			pg_free(sequence_script_file_name);
 			check_ok(ctx);
 		}