Clean up .gitignore (#3820)
Clean up .gitignore (#3820)

The coverage directory and local config file no longer exist.
KWierso/treeherder,edmorley/treeherder,KWierso/treeherder,edmorley/treeherder,edmorley/treeherder,edmorley/treeherder,KWierso/treeherder,KWierso/treeherder