boltdb: Improve node dumps
boltdb: Improve node dumps

Improve the node dumper by adding a verbosity value, sending the output to the
log, and always building the dumper code.

A verbosity of 2 gives the same output as before. Verbosity 3 gives a truncated
hexdump of the inodes.

Sending the output to the log is more flexible in that the log can be sent to a
file, which useful when the process is a spawned child.

By using conditions on constant variables the dumper code will be compiled to
catch build regressions.  The optimizer should remove the dead code when not
enabled.

Signed-off-by: Geoff Levand <c3918f39022407dee6a0056ceca9b1aa80e8e4ce@infradead.org>

glevand/coreos--etcd,glevand/coreos--etcd