Fix ows_geobbox_copy() to use correct sizeof()

The function should do a sizeof() of the structure, and not a pointer
to the structure. Raised by GCC 4.8

src/ows/ows_geobbox.c: In function ‘ows_geobbox_copy’:
src/ows/ows_geobbox.c:62:29: warning: argument to ‘sizeof’ in ‘memcpy’ call is the same pointer type ‘struct ows_geobbox *’ as the destination; expected ‘ows_geobbox’ or an explicit length [-Wsizeof-pointer-memaccess]
   return memcpy(c, g, sizeof(g));

Author: rouault

src/ows/ows_geobbox.c

@@ -58,8 +58,8 @@ ows_geobbox *ows_geobbox_copy(ows_geobbox *g)
   ows_geobbox *c;
 
   assert(g);
-  c = malloc(sizeof(g));
-  return memcpy(c, g, sizeof(g));
+  c = malloc(sizeof(*g));
+  return memcpy(c, g, sizeof(*g));
 }