repo 1.7.7.2

Fix AttributeError: 'HTTPError' object has no attribute 'reason'

Not every version of urllib2 supplies a reason object on the
HTTPError exception that it throws from urlopen().  Work around
this by using str(e) instead and hope the string formatting includes
sufficient information.

Change-Id: I0f4586dba0aa7152691b2371627c951f91fdfc8d
Signed-off-by: Shawn O. Pearce <sop@google.com>