eliminate trailing spaces and normalize initial spacing of examples (some had...

eliminate trailing spaces and normalize initial spacing of examples (some had five spaces, and the usual is four).

src/zc/buildout/buildout.txt

@@ -2189,7 +2189,7 @@ database is shown.
     ... parts =
     ... """)
 
-    >>> print system(buildout+' -vv'),
+    >>> print system(buildout+' -vv'), # doctest: +NORMALIZE_WHITESPACE
     Installing 'zc.buildout', 'setuptools'.
     We have a develop egg: zc.buildout 1.0.0.
     We have the best distribution that satisfies 'setuptools'.