Added OSLO config framework

This patch adds OSLO config framework required by
neutron-dynamic-routing repository for defining configuration
parameters.

Below changes are done as part of this patch-set:
 - Added OSLO config framework.
 - PEP8 changes for genconfig check.

Change-Id: Id3db0e9c5943ce913f5b2cca8d05a9ade37b3f68
Implements: blueprint bgp-spinout
Partial-Bug: #1560003

.gitignore

@@ -6,6 +6,7 @@ cover/
 covhtml/
 dist/
 doc/build
+etc/*.sample
 *.DS_Store
 *.pyc
 neutron.egg-info/

etc/README.txt

@@ -0,0 +1,9 @@
+To generate the sample neutron-dynamic-routing configuration files, run the
+following command from the top level of the neutron-dynamic-routing directory:
+
+tox -e genconfig
+
+If a 'tox' environment is unavailable, then you can run the following script
+instead to generate the configuration files:
+
+./tools/generate_config_file_samples.sh

etc/oslo-config-generator/bgp_dragent.ini

@@ -0,0 +1,5 @@
+[DEFAULT]
+output_file = etc/bgp_dragent.ini.sample
+wrap_width = 79
+
+namespace = bgp.agent

tox.ini

@@ -27,6 +27,7 @@ commands = sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasen
 commands =
   flake8
   neutron-db-manage --subproject neutron-dynamic-routing --database-connection sqlite:// check_migration
+  {[testenv:genconfig]commands}
 
 [testenv:i18n]
 commands = python ./tools/check_i18n.py ./neutron-dynamic-routing ./tools/i18n_cfg.py