Remove lib/cinder_backends/solidfire
Remove lib/cinder_backends/solidfire

This was something we used a while back, but since support
for sections was added to devstack local.conf parsing we
don't need this, and actually prefer just using the
sections in local.conf.

Here's an example of how to achieve the same thing via
local.conf sections:

CINDER_ENABLED_BACKENDS=solidfire
TEMPEST_VOLUME_DRIVER=SolidFireDriver
TEMPEST_VOLUME_VENDOR="SolidFire Inc"
TEMPEST_STORAGE_PROTOCOL=iSCSI

[[post-config|$CINDER_CONF]]
[DEFAULT]
CINDER_ENABLED_BACKENDS=solidfire
[solidfire]
volume_driver=cinder.volume.drivers.solidfire.SolidFireDriver
san_ip=192.168.160.3
san_login=admin
san_password=admin
volume_backend_name=solidfire

Change-Id: I8068fd4fb14510b15c31edf490283454f167f6c6

Mahito/devstack,dtroyer/devstack,bigswitch/devstack,noironetworks/devstack,openstack-dev/devstack,dtroyer/devstack,bswartz/devstack,nawawi/openstack,Mahito/devstack,bswartz/devstack,samgoon/devstack,dirkmueller/devstack,bigswitch/devstack,nawawi/openstack,richliu/devstack,openstack-dev/devstack,richliu/devstack,noironetworks/devstack,group-policy/devstack,samgoon/devstack,group-policy/devstack,dirkmueller/devstack