Oslo sync to recover from db2 server disconnects

A checkout listener can be added to sqlalchemy to be able to
handle database disconnect pessimistically and avoid an error in
the event of a DB restart or simply a temp connection issue due
to network glitches. At the moment only mysql is enabled with
this feature. This patch enables db2 as well.

Oslo version in change I5563360b43c4b648f5b035099b0e1d2e71d32503

Partial-Bug: #1231657
Change-Id: Idf8b3b11a06790813fed218bdbaf130554f80fa3
Implement the /v2/sample API

This is a simple implementation of the new sample endpoint in the API.
It provides raw accesses to the samples collected by Ceilometer, without
imposing any kind of filtering on the meter name.

The fields are also correctly named this time.

Change-Id: I9e01a082c04e0462811befd98899e2f2d4a4dc82
Blueprint: sample-api
api: raise ClientSideError rather than ValueError

This also enables the error message to be translatable.

Change-Id: If63ba0f7bc04eb490578c7598875407e796700aa
Ensure that the user/project exist on alarm update

This patch ensure that the user and project exists before updating the
alarm.

Closes bug #1260776

Change-Id: I25cf55d91b78a32bda671426972b7f418bf85e21
Move sphinxcontrib-httpdomain to test-requirements

The sphinxcontrib-httpdomain is now in the global-requirements list, so,
it'll be better to track *all* requirements in the corresponding files.

Change-Id: I6cd9eb8982cd49be1c59680a16d66acd30b9a29f
Imported Translations from Transifex

Change-Id: Icfae3ea229a737b69feb8efc6520f243320d93af
Merge "Oslo sync to recover from db2 server disconnects"
Ensure the correct error message is displayed

When a untranslated error message pass through the translation pecan
hook, the previous translated error is send to the client.

This patch fix that by reseting the "translatable_error" of the
translation pecan hook before each request.

Change-Id: Icee79cf09fd696655048c7c0cf8a3d6706e31701
Fixes: bug #1260398
Add metadata query validation limitation

There is currently no way to pre-determine the schema of
resource_metadata. So it will be hard to validate when
running a query. This patch includes this limitation in
ceilometer documentation.

Change-Id: I804467c3bb8e7d336ae881b25434063839951724
Partial-Bug: #1245367
Merge "Imported Translations from Transifex"
Merge "Move sphinxcontrib-httpdomain to test-requirements"
Convert event timestamp to PrecisionTimestamp

Before the timestamps for event and trait are stored in a Float
In mysql, the default precision won't work well, this one are rounded.

This patch, change the Float by the PrecisionTimestamp Column Type, like
the sample timestamp that demand the same precision.

And ensure that get_events always return datetime object.

Change-Id: I1f986784b07afa50bdbb7faa9499e7b614da8ec1
Merge "Add metadata query validation limitation"
Merge "Ensure that the user/project exist on alarm update"
Merge "Ensure the correct error message is displayed"
Merge "Convert event timestamp to PrecisionTimestamp"