Unfortunately, the standard way to install git-lfs doesn’t work on RPi2. But there is simple workaround:

# install go
sudo apt-get install golang
# you may want to grab a coffee at this stage... ;) 

# get git-lfs from github
sudo -i
mkdir /root/gocode
export GOPATH=/root/gocode
go get github.com/github/git-lfs
cp gocode/bin/git-lfs /usr/bin