change the order of OPM_UNUSED and variable name

it seems like some compilers (GCC 4.9.2?) are picky about this and
require

```c++
TypeName VariableName __attribute__ ((__unused__))
```

tests/models/test_quadrature.cpp

@@ -46,7 +46,7 @@
 #if HAVE_DUNE_ALUGRID
 #define EWOMS_NO_ALUGRID_UNUSED
 #else
-#define EWOMS_NO_ALUGRID_UNUSED OPM_UNUSED
+#define EWOMS_NO_ALUGRID_UNUSED  OPM_UNUSED
 #endif
 
 const unsigned dim = 3;