Compatibility with IDEA 15

(cherry picked from commit 5281edb)

Author: zolotov

src/com/goide/dlv/DlvDebugProcess.java

@@ -209,8 +209,6 @@ protected Promise<?> continueVm(@NotNull StepAction stepAction) {
  case IN:
  command(STEP);
  break;
- case IN_ASYNC:
- break;
  case OVER:
  command(NEXT);
  break;