Bugzilla bug #50386: fixed PR_Sleep so that it won't return uninitialized

variable.  Thanks to Fred Batty <fredb@iplanet.com> for reporting the bug.

nsprpub/pr/src/pthreads/ptthread.c

@@ -749,14 +749,13 @@ PR_IMPLEMENT(PRStatus) PR_Yield()
 
 PR_IMPLEMENT(PRStatus) PR_Sleep(PRIntervalTime ticks)
 {
-    PRStatus rv;
+    PRStatus rv = PR_SUCCESS;
 
     if (!_pr_initialized) _PR_ImplicitInitialization();
 
     if (PR_INTERVAL_NO_WAIT == ticks)
     {
         _PT_PTHREAD_YIELD();
-        rv = PR_SUCCESS;
     }
     else
     {