Add auto-generated files to .gitignore

When running "python setup.py <command>", some files are generated
automatically. They should be ignored from the version management.

Change-Id: I39862425babc988c57a2226c84a883a05bab9955

.gitignore

@@ -1,5 +1,8 @@
 /doc/build/
 /openstacki18n.egg-info/
+AUTHORS
+ChangeLog
+dist/
 
 *.mo