Automatic merge from submit-queue
update gazel usage in bazel.md
**What this PR does / why we need it**:
Now run the newest gazel have to specify the '-root' argument to update a single BUILD file.
So updated the gazel usage.
Automatic merge from submit-queue
Fix doc links in Federation readme
**What this PR does / why we need it**:
The user guide and admin guide links were swapped round
**Release note**: NONE
Automatic merge from submit-queue
Reduce verbosity of volume reconciler
**What this PR does / why we need it**:
It reduces the log verbosity for attaching of volumes
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #
**Special notes for your reviewer**:
**Release note**:
```release-note
Reduce verbosity of volume reconciler when attaching volumes
```
Set logging level for information about attaching of volumes to from 1 to 4
Otherwise the log is spammed with one line per 100ms while attaching is
in progress and afterwards as long as the volume is attached.
Automatic merge from submit-queue
update binding details to design/persistent-storage doc
Scroll down to "Matching and binding" (there is no TOC).
An issue I see is that this level of detail may get stale quickly and there is no built-in mechanism to update this doc when the binding code changes. However, several people on my team, from time to time, want to know greater details about binding rules, eg. for test writing, updating/creating other docs, etc.
PTAL @jsafrane @pmorie @copejon
If it's decided this type of content (high level overview of an algorithm/implementation) is useful, but docs/design/ is not the right location, perhaps a new dir can be created for this type of content?
