Fix db cursor double-open, causing yum to hang on reinstall (RhBug:678644)

Fix db cursor double-open, causing yum to hang on reinstall (RhBug:678644)
- A refactoring error in commit 475391dc581bf5ba72b6d59d16d875505b45bd51
  causes us to open a double cursor on the Package db. This doesn't
  seem to affect much in rpm context, but Yum is being naughty and holding
  two different handles to the same db simultaneously, which causes
  to deadlock on trying to lock the same record twice from two different
  handles .. or something to that effect.