Bug#663357: direct git repo support

[Osamu Aoki]

Hi,

Considering popularity of the git repo these days, this is nice thing to
add.  I need to make some trivial merge operation to get trhe reported
patch applied to the current source tree.  It will take some time.

(There are 52 bugs marked pending in devscripts.  Most of them are uscan
related bugs.  This is one of the last one to fix.)

The code base of proposed patch looks reasonable.

Osamu