merged the latest changes from plugin-framework branch - revision 39

merged the latest changes from plugin-framework branch - revision 39
conforming to the new cisco plugin directory structure and moving all db related modules into cisco/db folder
updated db_test_plugin.py
 - added import of cisco constants module
 - added LOG.getLogger for logging component name
 - updated import module paths for l2network_models/db and ucs_models/db to use the new directory structure
 - updated (rearranged) imports section to obey openstack alphabetical placement convention
updated db_conn.ini
 - updated database name from cisco_naas to quantum_l2network
unit test cases ran successfully and pep8 checks done again