Merge lp:~xnox/launchpadlib/fix-1471927 into lp:launchpadlib

[Dimitri John Ledkov]

Make sure query_string is always string.

=== modified file 'src/launchpadlib/credentials.py'
--- src/launchpadlib/credentials.py	2015-07-10 13:35:51 +0000
+++ src/launchpadlib/credentials.py	2015-07-11 19:11:15 +0000
@@ -248,6 +248,8 @@
     @classmethod
     def from_string(cls, query_string):
         """Create and return a new `AccessToken` from the given string."""
+        if not isinstance(query_string, str):
+            query_string = query_string.decode('utf-8')
         params = cgi.parse_qs(query_string, keep_blank_values=False)
         key = params['oauth_token']
         assert len(key) == 1, (