[swarming] fix log indent level
[swarming] fix log indent level

Need to see logs every time when BotInfo.dimensions_flat gets updated.

Bug: 1057346
Change-Id: Icfbf20f9f33a496bb9c5e1e88c703a363086ee6f
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-py/+/2084312
Auto-Submit: Junji Watanabe <aaef61ef98ffea505db831f310be2a0eb8492537@google.com>
Commit-Queue: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>
Reviewed-by: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>

luci/luci-py,luci/luci-py,luci/luci-py,luci/luci-py