pg_upgrade: simplify code layout in a few places

Backpatch-through: 9.4 (9.3 didn't need improving)

src/bin/pg_upgrade/exec.c

@@ -112,7 +112,6 @@ exec_prog(const char *log_file, const char *opt_log_file,
 	pg_log(PG_VERBOSE, "%s\n", cmd);
 
 #ifdef WIN32
-
 	/*
 	 * For some reason, Windows issues a file-in-use error if we write data to
 	 * the log file from a non-primary thread just before we create a
@@ -194,7 +193,6 @@ exec_prog(const char *log_file, const char *opt_log_file,
 	}
 
 #ifndef WIN32
-
 	/*
 	 * We can't do this on Windows because it will keep the "pg_ctl start"
 	 * output filename open until the server stops, so we do the \n\n above on

src/bin/pg_upgrade/server.c

@@ -310,12 +310,8 @@ start_postmaster(ClusterInfo *cluster, bool throw_error)
 	 * running.
 	 */
 	if (!pg_ctl_return)
-	{
-		if (cluster == &old_cluster)
-			pg_fatal("pg_ctl failed to start the source server, or connection failed\n");
-		else
-			pg_fatal("pg_ctl failed to start the target server, or connection failed\n");
-	}
+		pg_fatal("pg_ctl failed to start the %s server, or connection failed\n",
+			cluster == &old_cluster ? "source" : "target");
 
 	return true;
 }