Fix corrector_test.cc.

Fix two death tests dealing with the sign of the gradient.

Change-Id: Ic91d54a64cc509307c94fce6d1fca083078936e2

internal/ceres/corrector_test.cc

diff --git a/internal/ceres/corrector_test.cc b/internal/ceres/corrector_test.cc
index 55e7d6b..9355616 100644
--- a/internal/ceres/corrector_test.cc
+++ b/internal/ceres/corrector_test.cc
@@ -43,14 +43,14 @@
 
 // If rho[1] is zero, the Corrector constructor should crash.
 TEST(Corrector, ZeroGradientDeathTest) {
-  const double kRho[] = {0.0, 0.0, 0.0};
+  const double kRho[] = {0.0, 0.0, 1.0};
   EXPECT_DEATH_IF_SUPPORTED({Corrector c(1.0, kRho);},
                ".*");
 }
 
 // If rho[1] is negative, the Corrector constructor should crash.
 TEST(Corrector, NegativeGradientDeathTest) {
-  const double kRho[] = {0.0, -0.1, 0.0};
+  const double kRho[] = {0.0, -0.1, 1.0};
   EXPECT_DEATH_IF_SUPPORTED({Corrector c(1.0, kRho);},
                ".*");
 }