Use DEFAULT section for dispatcher in doc

Section of dispatcher is moved to DEFAULT in Icehouse, it is in
collector section in Havana but already deprecated. The
doc/source/install/manual.rst still put it in collector section
which seems not good.

Change-Id: I2c5c16c2ffe0dabd19966fc79ad88e418a43a6fd
Closes-Bug: #1269521
Fix to handle null threshold_rule values

check if threshold_rule and combination_rule values
are None and raise the right error in the validation
method instead of propagating it further causing
unhandled exceptions.

fixes bug #1238453

Change-Id: I70a397c89d974e489fd0ccc4ab28d73aed51443f
Implement the /v2/samples/<sample-id> 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 patch is about retreiving only one sample with the id.

The fields are also correctly named this time.

Change-Id: Ifdd7f024b066407cd42ec0572385f97acd312125
Blueprint: sample-api
Update oslo

This updates Oslo to the latest commit
997ab2776c9cad033234e28a92fb7bc0ef5bc4c0

It removes the test_service test file, as the behavior of restarting on
SIGHUP is dependent of openstack.common.service which has changed
recently, is already tested as part of oslo.incubator's tests.

Change-Id: I389c690f4febe9c69c1e2c39cd16961635469c75
Return trait type from Event api

fixes bug 1268032

Change-Id: I6949c1cdeab4d3b1916d90c02e12da79bda38e35
Convert alarm timestamp to PrecisionTimestamp

Before the timestamps for alarm are stored in a datetime
In mysql, datetimes have only second precision, and the datetimes are
rounded.

This patch, change the Datetime by the PrecisionTimestamp Column Type, like
the sample and the event timestamps that demand the same precision.

Change-Id: Iad10c621b276fc40b9965d01bc460bcc834b473a
Merge "Implement the /v2/samples/<sample-id> API"
Merge "Update oslo"
Merge "Fix to handle null threshold_rule values"
Merge "Use DEFAULT section for dispatcher in doc"
Merge "Return trait type from Event api"
Merge "Convert alarm timestamp to PrecisionTimestamp"