TT#61761 Fix urllib.request handling

Fixes:

| No attribute 'code' on urllib.request._HTTPResponse [attribute-error]

as reported by pytype.

The urllib module has been split into parts and renamed in Python 3 to
urllib.request, urllib.parse, and urllib.error, and therefore will fail
with:

| AttributeError: module 'urllib' has no attribute 'request'

This used to work only because other components loaded within repoapi
did the `import urllib.request` for us.

Also the errors were never reported as such, as e.g. 404 errors are
throwing an exception (instead of provided as return code as expected by
our code so far), which we didn't catch so far. And the arguments
provided to logger/ logging were incorrect (number vs string), so fix
this and also slightly improve the logging messages while at it.

JFTR, `import urllib.request` is py3k-only, which is fine for us though,
since repoapi is supporting only py3k nowadays.  We should also think
about migrating from urllib towards requests everywhere.

Change-Id: Ibc965daa94216aaad80758dba0f50a74d8658887

repoapi/utils.py

@@ -19,7 +19,8 @@ import logging
 import os
 import shutil
 import subprocess
-import urllib
+import urllib.request
+from urllib.error import HTTPError
 from django.conf import settings
 
 logger = logging.getLogger(__name__)
@@ -51,14 +52,18 @@ def dlfile(url, path):
 
 def openurl(url):
     req = urllib.request.Request(url)
-    logger.debug("url:[%s]", url)
-    response = urllib.request.urlopen(req)
-    if response.code > 199 and response.code < 300:
-        logger.debug("OK[%d] url: %s", url, response.code)
-        return True
-    else:
-        logger.error("Error[%d] retrieving %s", url, response.code)
-        return False
+    logger.debug("Trying to retrieve url: [%s]", url)
+    try:
+        response = urllib.request.urlopen(req)
+        if 199 < response.getcode() < 300:
+            logger.debug("OK[%d] URL[%s]", response.getcode(), url)
+            return True
+    except urllib.error.HTTPError as e:
+        logger.error('Error[%d] retrieving URL[%s]', e.getcode(), url)
+    except Exception:
+        logger.error("Fatal error retrieving URL[%s]", url)
+
+    return False
 
 
 def jenkins_remove_ppa(repo):