Fix a memory leak.
Fix a memory leak.

A new buffer is allocated for each dive, but only the last one is freed.
Since the code is already prepared to simply re-use the same buffer,
there is no need to allocate those extra buffers.

henrik242/libdivecomputer,glance-/libdivecomputer,henrik242/libdivecomputer,Poltsi/libdivecomputer-vms,glance-/libdivecomputer