fix possible buffer overflow in rename_dir_children()
fix possible buffer overflow in rename_dir_children()

cppcheck said:
[sqlfs.c:2254]: (error) Dangerous usage of 'new_path' (strncpy doesn't always 0-terminate it)

guardianproject/libsqlfs,spthaolt/libsqlfs,eighthave/libsqlfs,spthaolt/libsqlfs,eighthave/libsqlfs,eighthave/libsqlfs,guardianproject/libsqlfs,guardianproject/libsqlfs,spthaolt/libsqlfs,guardianproject/libsqlfs,eighthave/libsqlfs,eighthave/libsqlfs,spthaolt/libsqlfs,guardianproject/libsqlfs,spthaolt/libsqlfs