GIT updates

[seanshpark]

Gather more about git

[seanshpark]

To revert submodule to master

1. checkout the commit you want to go
2. run git submodule update

git status will show detached branch but your parent repo will be fine

[seanshpark]

sed -i s/Signed-off-by/ONE-DCO-1.0-Signed-off-by/g $1