Fix several issues found by pylint

Includes fixes for:
- bad indentation
- wrong continued indentation
- old-style-class
- bad and trailing whitespaces
- import only what's needed
- unused imports
- unused variables
- superfluous-parens
- multiple-statements in one line
- too long lines

Also included:
- use UNIX instead of Windows line endings
- add .gitignore
Added these files to get them ignored e.g. on git status. These are very common also in other git repos of ceph. Since the repo doesn't include such files, ignore them.