clockfix: Fix regression introduced in r9280.

A cleanup wrongly removed pthread_cond_init(). Unfortunately we
used the function in only one place so the brekage was not spectacular
and took me a day to track down.

git-svn-id: http://streamboard.de.vu/svn/oscam/trunk@9299 4b0bc96b-bc66-0410-9d44-ebda105a78c1