persistence of l2network & ucs plugins using mysql

- db_conn.ini - configuration details of making a connection to the database
- db_test_plugin.py - contains abstraction methods for storing database values in a dict and unit test cases for DB testing
- l2network_db.py - db methods for l2network models
- l2network_models.py - class definitions for the l2 network tables
- ucs_db.py - db methods for ucs models
- ucs_models.py - class definition for the ucs tables
dynamic loading of the 2nd layer plugin db's based on passed arguments
Create, Delete, Get, Getall, Update database methods at - Quantum, L2Network and Ucs
Unit test cases for create, delete, getall and update operations for L2Network and Ucs plugins
pep8 checks done
branch based off revision 34 plugin-framework

changes after review comments -
merged the latest changes from plugin-framework branch - revision 39
confirming to the new directory structure and moving all db related modules into cisco/db folder
updated db_test_plugin.py
 - added import of cisco constants module
 - added getLogger to LOG 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

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added:
  quantum/plugins/cisco/db/db_conn.ini
  quantum/plugins/cisco/db/db_test_plugin.py
  quantum/plugins/cisco/db/l2network_db.py
  quantum/plugins/cisco/db/l2network_models.py
  quantum/plugins/cisco/db/ucs_db.py
  quantum/plugins/cisco/db/ucs_models.py
modified:
  quantum/plugins/cisco/README
pending merges:
  rohitagarwalla 2011-07-31 [merge] merged the latest changes from plugin-framework branch - revision 39
    rohitagarwalla 2011-07-29 persistence of l2network & ucs plugins using mysql