Accept non perfectness of urllib2.

src/zc/buildout/networkcache.txt

@@ -197,6 +197,9 @@ Now lets clean up buildout directory:
 
 In case if download cache is failing, original resources are used:
 
+(Note: Due to usage of urllib2 during download which "eats" real socket error
+message not perfect error is shown like <urlopen...Connection Refused>)
+
    >>> write(sample_buildout, 'buildout.cfg',
    ... '''
    ... [buildout]
@@ -222,13 +225,13 @@ In case if download cache is failing, original resources are used:
    Installing eggs.
    Getting distribution for 'demo'.
    Downloading demo-0.4c1-py2.7.egg from network cache.
-   Failed to download from network cache demo-0.4c1-py2.7.egg: [Errno 111] Connection refused
+   Failed to download from network cache demo-0.4c1-py2.7.egg: <urlopen error [Errno 111] Connection refused>
    Uploading http://localhost/demo-0.4c1-py2.7.egg into network cache.
    Fail to upload file. [Errno 111] Connection refused
    Got demo 0.4c1.
    Getting distribution for 'demoneeded'.
    Downloading demoneeded-1.2c1.zip from network cache.
-   Failed to download from network cache demoneeded-1.2c1.zip: [Errno 111] Connection refused
+   Failed to download from network cache demoneeded-1.2c1.zip: <urlopen error [Errno 111] Connection refused>
    Uploading http://localhost/demoneeded-1.2c1.zip into network cache.
    Fail to upload file. [Errno 111] Connection refused
    Got demoneeded 1.2c1.