Fix a logging bug in parameter_block.h

Not entirely sure how and why this was compiling up till now.

Thanks to Carlos Hernandez for reporting this.

Change-Id: Ieadbb8cb0a3769afe9dcef927ff0287342e44f1f
diff --git a/internal/ceres/parameter_block.h b/internal/ceres/parameter_block.h
index b1e8d93..695fa6f 100644
--- a/internal/ceres/parameter_block.h
+++ b/internal/ceres/parameter_block.h
@@ -173,8 +173,8 @@
           new double[local_parameterization_->GlobalSize() *
                      local_parameterization_->LocalSize()]);
       CHECK(UpdateLocalParameterizationJacobian())
-          "Local parameterization Jacobian computation failed"
-          "for x: " << ConstVectorRef(state_, Size()).transpose();
+          << "Local parameterization Jacobian computation failed for x: "
+          << ConstVectorRef(state_, Size()).transpose();
     } else {
       // Ignore the case that the parameterizations match.
     }