[Chromoting] Add version stamps to Mac installer and host scripts.

remoting/host/installer/mac/Scripts/remoting_preflight.sh

 #!/bin/sh
 
 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+# Version = @@VERSION@@
+
 HELPERTOOLS=/Library/PrivilegedHelperTools
 NAME=org.chromium.chromoting
 CONFIG_FILE="$HELPERTOOLS/$NAME.json"
 PLIST=/Library/LaunchAgents/org.chromium.chromoting.plist
 ENABLED_FILE="$HELPERTOOLS/$NAME.me2me_enabled"
 ENABLED_FILE_BACKUP="$ENABLED_FILE.backup"
 
 trap onexit ERR
 
 function onexit {
   # Log an error but don't report an install failure if this script has errors.
   logger An error occurred while launching the service
   exit 0
 }
 
+logger Running Chrome Remote Desktop preflight script @@VERSION@@
+
 # If there is an _enabled file, rename it while upgrading.
 if [[ -f "$ENABLED_FILE" ]]; then
   mv "$ENABLED_FILE" "$ENABLED_FILE_BACKUP"
 fi
 
 # Stop and unload the service.
 set `ps aux | grep loginwindow.app | grep -v grep`
 USERNAME=$1
 USERID=$2
 if [[ -n "$USERNAME" && -n "$USERID" ]]; then
   launchctl bsexec "$USERID" sudo -u "$USERNAME" launchctl stop "$NAME"
   launchctl bsexec "$USERID" sudo -u "$USERNAME" launchctl unload -w -S Aqua "$PLIST"
 fi