[autotest] fix a typo in a test name in perf dashboard config

build_RootFileSystemSize -> build_RootFilesystemSize

BUG=chromium:383192
TEST=unittest

Change-Id: Ie0c53ff1c7c27de2f9a64089788ecabeda3d5a5a
Reviewed-on: https://chromium-review.googlesource.com/203378
Reviewed-by: Don Garrett <dgarrett@chromium.org>
Commit-Queue: Fang Deng <fdeng@chromium.org>
Tested-by: Fang Deng <fdeng@chromium.org>
1 file changed