worktree: enable manual ignore patterns when no .gitignore is available
worktree: enable manual ignore patterns when no .gitignore is available

Signed-off-by: Fabian Sabau <4e2e62426d025c03b337f33f6bf0e0d7dbd5ffd7@gmail.com>

src-d/go-git,go-git/go-git,mcuadros/go-git,go-git/go-git,mcuadros/go-git,src-d/go-git