Fix bug with sleep - wake is not cleared after it occurs

Do not initialize waitcondition with capacity

src/context/switch.rs

@@ -45,6 +45,7 @@ pub unsafe fn switch() -> bool {
 
                 let current = arch::time::monotonic();
                 if current.0 > wake.0 || (current.0 == wake.0 && current.1 >= wake.1) {
+                    context.wake = None;
                     context.unblock();
                 }
             }

src/sync/wait_condition.rs

@@ -12,7 +12,7 @@ pub struct WaitCondition {
 impl WaitCondition {
     pub fn new() -> WaitCondition {
         WaitCondition {
-            contexts: Mutex::new(Vec::with_capacity(16))
+            contexts: Mutex::new(Vec::new())
         }
     }