Address errors, improvements, formatting

- Removed unused code not portable due to buffer() use
- raw_input() does not exist in Python 3
- Fixed octal constant syntax for Python 3
- Fixed TypeError
- Replace if not exists: makedirs(path) with single call: using makedirs(path, exist_ok=True)
- Class inherits from object, can be safely removed from bases in python3: pylint's useless-object-inheritance (W0235) check

Signed-off-by: JoeLametta <JoeLametta@users.noreply.github.com>

whipper/common/common.py

@@ -292,7 +292,7 @@ def validate_template(template, kind):
                          'variable(s): {}'.format(', '.join(matches)))
 
 
-class VersionGetter(object):
+class VersionGetter:
     """
     I get the version of a program by looking for it in command output
     according to a regexp.