core: Remove resolved FIXME around port destruction

src/libcore/comm.rs

@@ -106,8 +106,6 @@ fn listen<T: send, U>(f: fn(chan<T>) -> U) -> U {
         rustrt::rust_port_begin_detach(self.po, yieldp);
         if yield != 0u {
             // Need to wait for the port to be detached
-            // FIXME: If this fails then we're going to leave our port
-            // in a bogus state. (Issue #1988)
             task::yield();
         }
         rustrt::rust_port_end_detach(self.po);