Whenever you do
sudo apt-get install git-core
on Ubuntu you will only get git version 1.7.5.x. I needed 1.7.6%2B.
To do this you have to run the following commands:
sudo apt-get install software-properties-common python-software-properties
sudo add-apt-repository ppa:git-core/ppa
sudo apt-get update
sudo apt-get install git-core
This should give you git version 1.7.11 (as of today)