Add repo script.

N/A

How to get gotoos sources:
1.Download and config repo:
1).Create a directory:
    $ mkdir ~/bin
2).Config environment variable:
    $ vim ~/.bashrc, add PATH=~/bin:$PATH to the end of ~/.bashrc
3).Download repo script, this maybe not up-to-date file, you can update to url:
    $ curl https://dl-ssl.google.com/dl/googlesource/git-repo/repo > ~/bin/repo
4).Add executable authority:
    $ chmod a+x ~/bin/repo

2.Sync gotoos sources:
1).Create a directory:
    $ mkdir ~/gotoos
2).Repo init:
    $ repo init -u https://github.com/gotoos/manifest.git -b master
3).Repo sync:
    $ repo sync -j4

Signed-off-by: liminghao <liminghao@xiaomi.com>
Remove some not use messages.

N/A

Signed-off-by: liminghao <liminghao@xiaomi.com>