Fix error adding to existing set in update_item

Values should be able to be added to existing set attribute for update_item.
Values in ADD action will be merged with existing values.

Closes-Bug: #1375985

Change-Id: Ibe9d86ab00baf702b2c628f39edb9197c9779fd8
Add 'last_updated' to 'table_info'

Update table status to *_FAILED if it stucks
to CREATING/DELETING state for a long time

Implements blueprint: table-info-timestamp

Change-Id: I03659858285082e3eca88846bea3c8fb7a3009cf
Application log rotation

Adds documentation about configuring application log rotation

Implements: bp log-rotating
Change-Id: Ib6b18d72346dc1de1d28df8923eaa46282039c8c
Merge "Add 'last_updated' to 'table_info'"
Merge "Application log rotation"
Use oslo.notify for notifications

Change-Id: I5a88204202ae6bfd19bb12c4e068e88960683eee
Blueprint: oslo-notify