pep8: Fix E127 continuation line over-indented

There are a bunch of these remaining, but I don't think the right course is
to 'fix' all of them to make pep8 happy, but instead to either change
the test in pep8 to consider that a continuation line may itself
be continued halfway, OR, to change the code in these lines to be more
readable by removing the need for all those nested continuations.

Personally, I find multiply-broken lines (aka nested continuations) really
hard to read.

mininet/net.py

@@ -423,7 +423,7 @@ class Mininet( object ):
         m = re.search( r, pingOutput )
         if m is None:
             error( '*** Error: could not parse ping output: %s\n' %
-                     pingOutput )
+                   pingOutput )
             return (1, 0)
         sent, received = int( m.group( 1 ) ), int( m.group( 2 ) )
         return sent, received