Fixed update extension process related issues

[siddheshwar-more]

Implemented changes to use old version extensions settings file during update process.
Example-
Current extension is 1204.12.1.1
User requested update for extension 1205.12.2.1

In above case WaAgent will -

1. run disable on old extension 1204.12.1.1
2. run update command on 1205.12.2.1 and this should use previous version (i.e 1204.12.1.1) 0.settings file to get 'autoUpadteChef' and 'deleteChefConfig' options value
   .
   Currently update process trying to read 0.settings from newly downloaded extension, and this fails as this settings file not available during update, because WaAgent takes some time to create it.