git-clean: add tests for relative path
git-clean: add tests for relative path

This adds tests for recent change by Dmitry to fix the report "git
clean" gives on removed paths, and also makes sure the command detects
paths that is outside working tree.

Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git