* Add config params for custom refspecs
* Add exceptions for errors encountered modifying git config
* Make the refspecs a configurable parameter
* Make refspecs a per-remote parameter
* Update master config template to include custom refspecs opts
* Add documentation for new config params
* Update GitFS walkthrough with a section on custom refspecs
* Remove dulwich support from salt.utils.gitfs
Dulwich still lacks important features, including (but not limited to)
the following:
- Lack of the necessary support for checking out a ref needed for
git_pillar/winrepo support
- No support in its config objects for multivar git config items, making
it impossible to detect when repos have multiple refspecs set for a
given git remote
Given this information, and the fact that it trails as a distant third
to Pygit2 and GitPython, Salt will cease to support Dulwich as a git
interface moving forward.
* Excise references to dulwich from documentation
* Add mention of custom refspecs to Nitrogen release notes
* Add gitfs_refspecs to mocked opts in gitfs integration tests
Also remove dulwich from unit tests
* Add information about opts argument not being intended for CLI use
