Avoid using deprecated Q_AGENT_EXTRA_AGENT_OPTS in ML2 setup

Q_AGENT_EXTRA_AGENT_OPTS is deprecated now and stack.sh displays
the warning that it will be removed early in "K" cycle.
Neutron ML2 devstack uses Q_AGENT_EXTRA_AGENT_OPTS to pass tunnel
configurations to Neutron plugin agents.

This commit removes the usage of Q_AGENT_EXTRA_AGENT_OPTS and
configures these config options directly.

Change-Id: I7fc1613ff78c0a8b1e80cc041b06f5d4680c34f2
Closes-Bug: #1354670
Set display name in apache processes

This change makes apache set process group name in the process name,
so when listing the processes the user can easily identify what's
running in each apache process. This is specially useful to debug
memory consumption or when a process consumming too much CPU.

Change-Id: I9787980052f451f452d3b8e5e51385ad5aa01e6a
Add ability to switch database driver

Also added mysqlconnector packages into default installation.

blueprint enable-mysql-connector

Change-Id: Ib2cda7cb183dc8f0ff4759cc6e9ecab469fd121c
Remove code tagged as "can be removed after Icehouse"

Change-Id: Ib78f3d55c9dcd46e0dfc3343c32e077cf530b5f7
Allow cinder types to be created without be file

3rd party ci tests have not whitelisted errors:
"Not Whitelisted Volume type with name * could not be found."

These are creating noise. Instead of requiring a backend file
for each vendor, remove the if statement and just create the
necessary type for each defined back-end.

Change-Id: Ic88efa20eb53864e4f3d22d3306841797dcd118d
enable multiple collector workers

currently, a single worker thread writes received samples into
database. this is fine for most occasions but during message
spikes, it is not enough. this patch increase amount of workers to
half the number of processors (so we can ensure ceilometer maintains
lightweight design)

this will also help validate mulitple worker setup works.

Partial-Bug: #1336755
Change-Id: I33037f2f9ebfda43238e5cd0cff75adbed65d055
Guard for worlddump in case LOGDIR is undefined

If LOGDIR is undefined, we'll end up calling worldump with the `-d` option but
pass in an empty string as the option value. This causes an argument parsing
error inside worlddump.

The proposed fix is to detect if LOGDIR is undefined, and if so, omit the `-d`
argument.

Change-Id: I77968849ebd3e3bebd2e5929b87b60fc1b6541bf
Closes-Bug: 1333321
Merge "Guard for worlddump in case LOGDIR is undefined"
Merge "Add ability to switch database driver"
Merge "Allow cinder types to be created without be file"
Merge "Remove code tagged as "can be removed after Icehouse""
Merge "Set display name in apache processes"
Merge "Avoid using deprecated Q_AGENT_EXTRA_AGENT_OPTS in ML2 setup"
Merge "enable multiple collector workers"
Merge branch 'master' of https://github.com/openstack-dev/devstack