GitLab

* gitfast: use $OSTYPE again

In the last update to upstream this was reverted:

 a56eac7a

 (Use OSTYPE instead of uname whenever possible for better speed. (#5496))
Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>

* gitfast: simplify plugin

No need to set and unset a variable we use once.
Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>

* gitfast: add script to update from upstream

This would make easier the process of updating, and also not miss our
patches.
Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>

* gitfast: update to upstream v2.21
Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>

* Stop loading git plugin
* Update completion and git-prompt to v2.10
* Update completion to v2.14

Certain themes need the 'clean' mark, and some people like to have the
'dirty' one, just like the original git_promp_info().

We probably shouldn't be modifying that function, there's no other clean
way to achieve our own status information, so let's try to emulate the
original as much as possible.
Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>

Using the upstream git completion and prompt stuff.
Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>