As Openstack projects continue to have longer database migration
chains, the Puppet default timeout of 300 seconds for an execution
is becoming too short a duration on some hardware, leading to timeouts.
As projects continue to add more migration scripts without pruning
the base, timeouts will continue to become more frequent unless
this time can be expanded.
Change-Id: I96c77a3d0fc43b16b323878996e8471a6a292a3d
Closes-Bug: #1904962