changegroup: pass ellipsis roots into cgpacker constructor
And rename the internal variable to conform with naming conventions.
Differential Revision: https://phab.mercurial-scm.org/D4089
# See http://EditorConfig.org for the specification
root = true
[*.py]
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indent_style = space
trim_trailing_whitespace = true
[*.{c,h}]
indent_size = 8
indent_style = tab
trim_trailing_whitespace = true
[*.t]
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indent_style = space
trim_trailing_whitespace = false