Fix early return in DoglegStrategy::StepAccepted

In StepAccepted, reuse_ was not cleared if the improvement was not good
enough. This is obviously wrong as the step was taken nevertheless and
the computed entities may be completely different at the new iterate.

Change-Id: I4bf3441f71550a0595dd8c5565aedd38d03e8b2f

internal/ceres/dogleg_strategy.cc

diff --git a/internal/ceres/dogleg_strategy.cc b/internal/ceres/dogleg_strategy.cc
index 1687bcd..620bda7 100644
--- a/internal/ceres/dogleg_strategy.cc
+++ b/internal/ceres/dogleg_strategy.cc
@@ -286,7 +286,6 @@
   CHECK_GT(step_quality, 0.0);
   if (step_quality < decrease_threshold_) {
     radius_ *= 0.5;
-    return;
   }
 
   if (step_quality > increase_threshold_) {