fix nccl unittest acc test=develop

python/paddle/fluid/tests/unittests/test_dist_base.py

@@ -442,10 +442,10 @@ class TestDistBase(unittest.TestCase):
         tr_cmd = "%s %s --role trainer --endpoints %s --trainer_id %d --current_endpoint %s --update_method nccl2 --lr %f"
         tr0_cmd = tr_cmd % \
                   (self._python_interp, model, self._ps_endpoints,
-                   0, w0_ep, self._lr / 2)
+                   0, w0_ep, self._lr)
         tr1_cmd = tr_cmd % \
                   (self._python_interp, model, self._ps_endpoints,
-                   1, w1_ep, self._lr / 2)
+                   1, w1_ep, self._lr)
 
         if self._mem_opt:
             tr0_cmd += " --mem_opt"