Fix some warnings under +w1 HP-UX compile

This is the world's fussiest compiler with +w1

Warnings reported by Richard Lloyd.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

src/search.cpp

@@ -2774,7 +2774,7 @@ namespace {
         }
 
         // Wait until the thread has finished launching and is gone to sleep
-        while (threads[i].state != THREAD_SLEEPING);
+        while (threads[i].state != THREAD_SLEEPING) {}
     }
   }
 
@@ -2815,7 +2815,7 @@ namespace {
 
     SplitPoint* sp;
 
-    for (sp = threads[threadID].splitPoint; sp && !sp->stopRequest; sp = sp->parent);
+    for (sp = threads[threadID].splitPoint; sp && !sp->stopRequest; sp = sp->parent) {}
     return sp != NULL;
   }