Allow collector service database connection retry

At the startup collector service loads the database dispatcher,
if the DB is offline momentarily the collector service starts but
continues to run with out having the ability to re-try the DB
connection. This fix will allow the connection to be retried next
time when collector service attempts to write to the database.

Change-Id: I10fef61a9c525e1c84d8cadbca86d6bde84927ba
Closes-Bug: 1301777
remove reference to model in migration

the model represents the current active representation.
migrations on the other hand represent some moment in past that
may or may not reflect the current model. we shouldn't reference
model unless we have to.

Change-Id: I78dca9043014acc1a6eda479f687f63d31ce1ea7
support request-id

enable request-id similar to other OpenStack projects to help
track specific requests.

Change-Id: Ie5126ff462eef70400e45d2966aa16d1c7345618
Closes-Bug: #1244182
Updated from global requirements

Change-Id: If5d93a882ca29a76d33a02b789d08295ea7f5cd1
Merge "Allow collector service database connection retry"
Merge "remove reference to model in migration"
Merge "support request-id"
Merge "Updated from global requirements"