Various fixes repored by Markus Moll.

1. Termination type was using == instead of =.
2. LevenbergMarquardtStrategyTest was using an object
   which was not returning the correct value.
3. DumpLinearLeastSquaresProblemToTextFile was passing an
   unnecessary argument to StringAppendF.

Change-Id: Ie7598c8e3d504763c889737a0d5cec805d52bbaf
diff --git a/internal/ceres/solver_impl.cc b/internal/ceres/solver_impl.cc
index ab91681..982fb40 100644
--- a/internal/ceres/solver_impl.cc
+++ b/internal/ceres/solver_impl.cc
@@ -216,7 +216,7 @@
   if (!program->CopyUserStateToParameterBlocks())  {
     // This can only happen if there was a numerical problem updating the local
     // jacobians. Indicate as such and fail out.
-    summary->termination_type == NUMERICAL_FAILURE;
+    summary->termination_type = NUMERICAL_FAILURE;
     summary->error = "Local parameterization failure.";
     return;
   }