Fix unit for vpn connection metric

Unit for vpn connections should use connection
instead of vpn. The docs show the right value.

Change-Id: I45482ca173347a351fcf0de5e9ee3faa8976600f
Update documentation for new transformer

This patch adds documentation for the new multi-meter arithmetic
transformer.

Change-Id: I8e6f6040ad9865ed5e57a2462a4d2eb5ad56e11c
Closes-Bug: #1346883
[HBase] Improve uniqueness for row in meter table

Currently, row in meter table consists of reversed timestamp,
meter and an md5 of user+resource+project for purposes of
uniqueness. But md5 of user+resource+project may be the same
for different meters and only "rts" provides the difference.
But in the tests or under the high load different meters
from the same user, resource and project may have the same
timestamp.
In this patchset row contains a message signature instead of
md5 of user+resource+project, because message signature has
dependecies from all fields of sample, it provides more uniqueness.

Change-Id: Ic767b257176e05c0b35664968e7f529f507eab11
Handle Cinder attach and detach notifications

Handle attach and detach Cinder notifications so
the latest volume state is available in samples.

Closes-bug: #1353590
Change-Id: I725d04bee332429e864941199e37aef07a0f6adf
Add message translate module in vmware inspector

Change-Id: I2d3a202aea0ecccf543a8ca20ab9dbceb1664939
Merge "[HBase] Improve uniqueness for row in meter table"
Merge "Add message translate module in vmware inspector"
Merge "Fix unit for vpn connection metric"
Merge "Handle Cinder attach and detach notifications"
Merge "Update documentation for new transformer"