Fix nightly run failure on sharpness_test

The test checks the PSNR thresholds instead of rate-distortion
performance, hence is broken when the underly design changes.

This commit lowers the PSNR threshold to fix the nightly run, as
the main value of this unit test is to run through the encoding
process under such conditions.

Change-Id: Icc3e253108e52686ca1f680ef98d5ce8ea268853
diff --git a/test/sharpness_test.cc b/test/sharpness_test.cc
index e74609b..a487dc2 100644
--- a/test/sharpness_test.cc
+++ b/test/sharpness_test.cc
@@ -34,7 +34,7 @@
                        { static_cast<int>(::libaom_test::kAllIntra),
                          { { 3, { { 2, 42.3 }, { 5, 42.4 } } },
                            { 6, { { 2, 41.8 }, { 4, 41.9 }, { 5, 41.9 } } },
-                           { 9, { { 2, 41.4 }, { 5, 41.4 } } } } } };
+                           { 9, { { 2, 41.3 }, { 5, 41.3 } } } } } };
 
 // This class is used to test sharpness parameter configured through control
 // call using AOME_SET_SHARPNESS for different encoder configurations.