Update filesync.py

ST3 does not extract the .sublime-package in Installed Packages folder, so the rename_sidebar_menu fails (shutil.move() command )
This behavior has been documented in [this issue](https://github.com/SublimeLinter/SublimeLinter-for-ST2/issues/374)
Merge pull request #21 from lsimone/patch-1

Update filesync.py