bootperf: fix showbootdata arg parse for directories.

The positional argument for results directories should be parsed as
nargs="*" to return an array. This fixes showbootdata not running from
the bootperf results dir.

BUG=b:166744231, b:161488133
TEST=showbootdata <bootperf result>

Change-Id: I9f47bef9551fae876779428f45ea9b6009967663
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crostestutils/+/2772415
Reviewed-by: Kuang-che Wu <kcwu@chromium.org>
Tested-by: Chinglin Yu <chinglinyu@chromium.org>
Commit-Queue: Chinglin Yu <chinglinyu@chromium.org>
1 file changed