taskprocessor.c: Simplify ast_taskprocessor_get() return code.

Change-Id: Id5bd18ef1f60ef8be453e677e98478298358a9d1

main/taskprocessor.c

@@ -713,12 +713,7 @@ struct ast_taskprocessor *ast_taskprocessor_get(const char *name, enum ast_tps_o
 	}
 
 	p = __allocate_taskprocessor(name, listener);
-	if (!p) {
-		ao2_ref(listener, -1);
-		return NULL;
-	}
 
-	/* Unref listener here since the taskprocessor has gained a reference to the listener */
 	ao2_ref(listener, -1);
 	return p;
 }