Fixed buggy typo

objectstore/TapePool.cpp

@@ -129,7 +129,7 @@ void cta::objectstore::TapePool::removeTapeAndCommit(const std::string& vid) {
           << vid << " found: " << t.getVid();
       throw WrongTape(err.str());
     }
-    if(t.isEmpty()) {
+    if(!t.isEmpty()) {
       throw exception::Exception("Cannot delete the tape: it has queued retrieve jobs");
     }
     // We can now delete the tape