Add variable to include/exclude --no-gitinfofile option.

[AlexSkrypnyk]

--no-gitinfofile option for drush make is used to include module version information and a last version commit timestamp.

Problem
Currently --no-gitinfofile is specified by default making dependency version resolution impossible as there is no information about versions provided. As a result, drush spits out anoying messages like the one below

Feeds entity processor requires this module and version. Currently   [warning]
using Feeds version  (Currently using Unresolved dependency Feeds
(Version >=7.x-2.0-beta1 required))

Solution
Add variable to allow optional inclusion of such CLI option. Whether to have it specified or not by default - can be discussed separately, but I personally would not want to have it specified by default as it breaks internal Drupal dependency discovery mechanisms by removing module versions.

PR is coming