Free allocated MatrixPrec

Let's set a good example in our examples

Signed-off-by: Carl Pearson <cwpears@sandia.gov>

example/gmres/test_prec.cpp

@@ -126,6 +126,7 @@ int main(int argc, char* argv[]) {
     if (endRes < convTol && numIters == 1) {
       pass = true;
     }
+    delete myPrec;
   }
   Kokkos::finalize();