MemArena.cpp: Fix Bus Error when running on Beaglebone/Beaglebone Black

* Similar to commit 178891b576 when running the
  emulator a "Bus Error" would be given andn will cause a seg fault immediately.
* When running on the BB change the path of the ram temp file to a valid
  location.

Signed-off-by: Franklin S Cooper Jr <fcooper27@gmail.com>

Common/MemArena.cpp

@@ -99,6 +99,8 @@ int ashmem_unpin_region(int fd, size_t offset, size_t len)
 // do not make this "static"
 #ifdef MAEMO
 std::string ram_temp_file = "/home/user/gc_mem.tmp";
+#elif defined(BB)
+std::string ram_temp_file = "/home/root/gc_mem.tmp";
 #else
 std::string ram_temp_file = "/tmp/gc_mem.tmp";
 #endif