Fix getting pastebin paste visiblity

Pastebin somehow decided to use title instead of alt.
They are wrong. That attribute should at least tell "Private" or "Public" to
blind users. Well, another reason to use Weboob instead of their website!

modules/pastebin/pages.py

@@ -51,7 +51,7 @@ class PastePage(LoginPage):
         paste.contents = self.parser.select(self.document.getroot(),
                 '//textarea[@id="paste_code"]', 1, 'xpath').text
         visibility_text = self.parser.select(header,
-                '//div[@class="paste_box_line1"]//img', 1, 'xpath').attrib['alt']
+                '//div[@class="paste_box_line1"]//img', 1, 'xpath').attrib['title']
         if visibility_text.startswith('Public'):
             paste.public = True
         elif visibility_text.startswith('Private'):

modules/pastebin/test.py

@@ -56,6 +56,8 @@ class PastebinTest(BackendTest):
         p1 = self.backend.new_paste(None, title='ouiboube', contents=u'Weboob <test>¿¡', public=False)
         self.backend.post_paste(p1, max_age=600)
         assert p1.id
+        # not related to testing special chars, but check if the paste is
+        # really private since test_post() tests the contrary
         assert p1.public is False
 
         # this should use the raw method to get the contents