Bug#664542: Last changes didn't work

[Dominique Brazziel]

	Defining the URL opener in one module and trying to use it another
still resulted in namespace type errors (Global name 'changelog_opener'
not found, etc.).  One line change to 
UpdateManager/DistSpecific/changelog.py seems to work:

#connection = urllib2.urlopen(url)
connection = urllib2.build_opener().open(url)

I'm not sufficiently conversant with Python and the u-m code 
to either implement a second opener without proxy support  which would
be built once then used globally as needed.