rocshmem_config.h has a different include path when installed and built-dir (#186)

* rocshmem_config.h needs to be in a similar directory structure for
includes to work when building testers in build, and from an installed
library

* Do not change installed rocshmem.hpp

src/util.cpp

@@ -28,7 +28,7 @@
 #include <cstdlib>
 #include <vector>
 
-#include "rocshmem_config.h"  // NOLINT(build/include_subdir)
+#include "rocshmem/rocshmem_config.h"  // NOLINT(build/include_subdir)
 
 namespace rocshmem {