Use flake8 if available instead of pyflakes

With flake8, we can check for more issues and ignore those who are not
real issues.

This allowed me to find genuine errors in:
- modules/boursorama/pages/account_history.py
- modules/ing/pages/login.py
- weboob/tools/application/qt/qt.py
I left one in weboob/tools/browser/browser.py for the time being.

Some PEP8 fixes on other files.

modules/boursorama/pages/account_history.py

@@ -23,7 +23,6 @@ from datetime import date
 import re
 
 from weboob.tools.browser import BasePage
-from weboob.capabilities.bank import Transaction
 from weboob.tools.capabilities.bank.transactions import FrenchTransaction
 
 

modules/gazelle/pages/torrents.py

@@ -25,7 +25,7 @@ from logging import warning, debug
 try:
     from urlparse import parse_qs
 except ImportError:
-    from cgi import parse_qs
+    from cgi import parse_qs  # NOQA
 
 from weboob.tools.misc import html2text, get_bytes_size
 from weboob.capabilities.torrent import Torrent
@@ -69,7 +69,7 @@ class TorrentsPage(BasePage):
                             current_group += ' - '
                         current_group += a.text
                 elif tr.attrib.get('class', '').startswith('group_torrent') or \
-                     tr.attrib.get('class', '').startswith('torrent'):
+                        tr.attrib.get('class', '').startswith('torrent'):
                     tds = tr.findall('td')
 
                     title = current_group
@@ -100,9 +100,9 @@ class TorrentsPage(BasePage):
                             continue
                         id = '%s.%s' % (params['id'][0], m.group(1))
                     try:
-                        size, unit = tds[i+3].text.split()
+                        size, unit = tds[i + 3].text.split()
                     except ValueError:
-                        size, unit = tds[i+2].text.split()
+                        size, unit = tds[i + 2].text.split()
                     size = get_bytes_size(float(size.replace(',', '')), unit)
                     seeders = int(tds[-2].text)
                     leechers = int(tds[-1].text)
@@ -159,8 +159,8 @@ class TorrentsPage(BasePage):
                 torrent.seeders = int(tds[3].text)
                 torrent.leechers = int(tds[4].text)
                 break
-            elif not is_table and tr.attrib.get('class', '').startswith('torrent_widget') and \
-                                  tr.attrib.get('class', '').endswith('pad'):
+            elif not is_table and tr.attrib.get('class', '').startswith('torrent_widget') \
+                    and tr.attrib.get('class', '').endswith('pad'):
                 url = tr.cssselect('a[title=Download]')[0].attrib['href']
                 m = self.TORRENTID_REGEXP.match(url)
                 if not m:

modules/ina/pages/video.py

@@ -23,7 +23,7 @@ import re
 try:
     from urlparse import parse_qs
 except ImportError:
-    from cgi import parse_qs
+    from cgi import parse_qs  # NOQA
 
 from weboob.capabilities import NotAvailable
 from weboob.tools.browser import BasePage, BrokenPageError
@@ -87,6 +87,7 @@ class BaseVideoPage(BasePage):
     def get_description(self):
         raise NotImplementedError()
 
+
 class VideoPage(BaseVideoPage):
     URL_REGEXP = re.compile('http://www.ina.fr/(.+)\.html')
 

modules/ing/pages/login.py

@@ -104,8 +104,9 @@ class LoginPage(BasePage):
         self.browser.submit(nologin=True)
 
     def error(self):
-        error = self.document.find('//span[@class="error"]')
-        return error is not None
+        err = self.document.find('//span[@class="error"]')
+        return err is not None
+
 
 class LoginPage2(BasePage):
     def on_loaded(self):

modules/kickass/pages.py

@@ -21,7 +21,7 @@
 try:
     from urlparse import parse_qs
 except ImportError:
-    from cgi import parse_qs
+    from cgi import parse_qs  # NOQA
 
 from urlparse import urlsplit
 

modules/radiofrance/browser.py

@@ -29,7 +29,7 @@ import re
 try:
     from urlparse import parse_qs
 except ImportError:
-    from cgi import parse_qs
+    from cgi import parse_qs  # NOQA
 
 
 __all__ = ['RadioFranceBrowser', 'RadioFranceVideo']
@@ -93,7 +93,6 @@ class ReplayPage(BasePage):
                 return (radio_domain, player_id)
 
 
-
 class DataPage(BasePage):
     def get_current(self):
         document = self.document