[MERGE][Bug 59150] Fix test suite failing when paramiko is not installed

[Martin Pool]

Martin Pool has voted tweak.
Status is now: Conditionally approved
Comment:

+    if not url.startswith(actual + '://'):
+        raise AssertionError('url [%r] does not start with [%r]' % 
(url,
+ 
actual))

Thanks for changing that from an assertion.  Just a couple of quibbles 
though: the indentation of the second line is weird, and normally we 
would have just %r not [%r].  OK to merge though.

For details, see: 
http://bundlebuggy.aaronbentley.com/request/%3Cm2tzptlpw4.fsf%40free.fr%3E