Try Signing out and then back in in the CC desktop app.
In the account management part of the "preferences", sign out and back in and see if that helps.
Of course I tried multiple times to log out and back in - nothing worked.
I deinstalled LR, rebooted and tried to install LR again. The result: 2015 got installed.
Deinstalled it again, deinstalled also Photoshop CC. Reboot, install again - same result LR 2015 got installed and Cloud App told me that it is up to date. Deinstalled everything again, incl. Desktop Cloud App.
Downloaded Desktop CC App freshly, installed LR - result, you guess it: 2015 got installed and message was: up to date.
After I killed ALL CC Apps (PS, Bridge, LR, Die xtension Manager) from the System and deleted manually all the CC App and ALL left over CC Crap from System/Library and User/Library and started from scratch -LR 2015.1 finally got installed.
Really annoying experience..