Updating the no track or ref fix to match the buildstream style

William Salmonrequested to merge
willsalmon/APIFix into master

Removing core knowledge of plugin's and fixing the Git plugin.

Changes proposed in this merge request:

  • Remove the hasattr from the core to the plugin
  • Fix the git plugin so it fails to configure if it dose not have a track or ref.

This is related to #471 (closed) but dose not close it as this will then need back porting.

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