Use local wallet variable and open kwallet before using it.

kwallet could be None when using delete_password() as first usage of keyring.

--HG--
branch : fix_kwallet_delete
Corrected delete exception message

--HG--
branch : fix_kwallet_delete
Merged in msitarz/python-keyring-lib/fix_kwallet_delete (pull request #20: Fixes KWallet delete functionality)
Handle change of name of raw_input to input under python 3

--HG--
branch : issue_84
Select 'input' function based on Python version. Fixes #84

--HG--
extra : source : 8d001763b6b1be2b6ee83d3263b6bb1a9ed9c7c1
OSX backend py3 fix. Decode byte-string.

--HG--
extra : source : 7fb305d7eec2e81394f15fb90931ed9472c5deb7
Merge (preferring fix as implemented in default)
Update readme
Update version for 1.2.1 release
Added tag 1.2.1 for changeset 3f0bd46c9051