message: temp fix webService and add try catch
diff: @@ -123,7 +123,7 @@ class WebService(object):
  workdir,
  port=9292,
  gpus=None,
  - thread_num=2,
  + thread_num=4,
  mem_optim=True,
  use_lite=False,
  use_xpu=False,
  @@ -236,7 +236,7 @@ class WebService(object):
  use_lite=False,
  use_xpu=False,
  ir_optim=False,
  - thread_num=2,
  + thread_num=4,
  mem_optim=True,
  use_trt=False,
  gpu_multi_stream=False,
  