fix arr include

rok-cesnovar · rok-cesnovar · commit 54da5ef9c758 · 2020-01-11T12:07:00.000+01:00
diff --git a/src/test/interface/mpi_test.cpp b/src/test/interface/mpi_test.cpp
@@ -2,7 +2,7 @@
 
 #include <cmdstan/command.hpp>
 #include <gtest/gtest.h>
-#include <stan/math/prim/arr.hpp>
+#include <stan/math/prim.hpp>
 #include <test/test-models/proper.hpp>
 
 TEST(StanUiCommand, mpi_ready) {
