Threadpool: Initialize new dynamic workers

Although we were initializing worker threads during pool creating,
we missed this during virThreadPoolSendJob. This bug led to segmenation
fault as worker thread free() given argument.

src/util/threadpool.c

@@ -286,6 +286,7 @@ int virThreadPoolSendJob(virThreadPoolPtr pool,
                          void *jobData)
 {
     virThreadPoolJobPtr job;
+    struct virThreadPoolWorkerData *data = NULL;
 
     virMutexLock(&pool->mutex);
     if (pool->quit)
@@ -298,10 +299,20 @@ int virThreadPoolSendJob(virThreadPoolPtr pool,
             goto error;
         }
 
+        if (VIR_ALLOC(data) < 0) {
+            pool->nWorkers--;
+            virReportOOMError();
+            goto error;
+        }
+
+        data->pool = pool;
+        data->cond = &pool->cond;
+
         if (virThreadCreate(&pool->workers[pool->nWorkers - 1],
                             true,
                             virThreadPoolWorker,
-                            pool) < 0) {
+                            data) < 0) {
+            VIR_FREE(data);
             pool->nWorkers--;
             goto error;
         }