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/bcppcompiler.py

@@ -352,5 +352,4 @@ class BCPPCompiler(CCompiler) :
             try:
                 self.spawn(pp_args)
             except PackagingExecError as msg:
-                print(msg)
                 raise CompileError(msg)

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

Lib/packaging/compiler/unixccompiler.py

@@ -127,7 +127,7 @@ class UnixCCompiler(CCompiler):
         executables['ranlib'] = ["ranlib"]
 
     # Needed for the filename generation methods provided by the base
-    # class, CCompiler.  NB. whoever instantiates/uses a particular
+    # class, CCompiler.  XXX whoever instantiates/uses a particular
     # UnixCCompiler instance should set 'shared_lib_ext' -- we set a
     # reasonable common default here, but it's not necessarily used on all
     # Unices!