Set MySQL slow log to record every query

Since devstack is for development, lets record all SQL queries to enable
debugging, and further development.

Change-Id: Idb4078a0d3a84151ad4c506f8861637d84ae47ad
Merge "Set MySQL slow log to record every query"
Enable Identity v3 API

Change-Id: I78e0ed5f1baaf236bf95ddf73be764072674d732
Remove DEFAULT_STACK_USER, just use STACK_USER

STACK_USER needs to be set for more than just stack.sh, there
was no real distinction for using DEFAULT_STACK_USER instead
of just setting STACK_USER directly and allowing it to be
overridden in localrc.

Change-Id: I9e8d70db29bb421f1ce3dbf40a5ad299cc7ea785
Merge branch 'stack-user' into dt-test