Packaging cleanup: remove conditionals for < 2.6 support.

PEP 370 features and sys.dont_write_bytecode are always available
in 3.3; the distutils2 backport still has the conditionals.

I also renamed an internal misnamed method and fixed a few things
(“packaging2” name, stray print, unused import, fd leak).

Lib/packaging/compiler/ccompiler.py

@@ -5,7 +5,6 @@ interface for the compiler abstraction model used by packaging.
 """
 
 import os
-import sys
 from shutil import move
 from packaging import logger
 from packaging.util import split_quoted, execute, newer_group, spawn