Fix error message returned when using SUITE_SPARSE_QR in covariance estimation
on a ceres built without SuiteSparse support.

This is only a minor issue, up until now this case would have been handled by
the "default" case of the switch

Change-Id: Ib4568eb827dbf0e8e8d618a5bc8cd379a3c42c42

internal/ceres/covariance_impl.cc

diff --git a/internal/ceres/covariance_impl.cc b/internal/ceres/covariance_impl.cc
index cfa5ffc..8c083fa 100644
--- a/internal/ceres/covariance_impl.cc
+++ b/internal/ceres/covariance_impl.cc
@@ -533,8 +533,8 @@
   switch (options_.algorithm_type) {
     case DENSE_SVD:
       return ComputeCovarianceValuesUsingDenseSVD();
-#ifndef CERES_NO_SUITESPARSE
     case SUITE_SPARSE_QR:
+#ifndef CERES_NO_SUITESPARSE
       return ComputeCovarianceValuesUsingSuiteSparseQR();
 #else
       LOG(ERROR) << "SuiteSparse is required to use the "