[Bf-python] removing mesh verts crashes

[Campbell Barton]

With the 3ds importer, theres a problem removing the first vert (dummy 
vert added because of eekadoodle problem)
This is the BT from the crash

This is very easy to reproduce.
me = Mesh.Get('Cube')
me.verts.delete([0])
- Crash


#0  0xb7ae485c in memcpy () from //lib/libc.so.6
#1  0x08426f31 in CustomData_copy_data (source=0x8ed1c9c, dest=0xbfa36dd8,
    source_index=33752, dest_index=0, count=33751) at customdata.c:706
#2  0x083b3963 in delete_verts (mesh=0x8ed1c20, vert_table=0xb5247028,
    to_delete=1) at Mesh.c:347
#3  0x083b4855 in MVertSeq_delete (self=0xb6f88db8, args=0xb4c8004c)
    at Mesh.c:1865
#4  0x08708cab in PyEval_EvalFrame (f=0x8b5f9c4) at Python/ceval.c:3563
#5  0x08709e15 in PyEval_EvalCodeEx (co=0xb635c8e0, globals=0xb6fc2dfc,
    locals=0x0, args=0xb635e5f8, argcount=1, kws=0x0, kwcount=0,
    defs=0xb63629b8, defcount=1, closure=0x0) at Python/ceval.c:2736
#6  0x08754c59 in function_call (func=0xb6f69e2c, arg=0xb635e5ec, kw=0x0)
    at Objects/funcobject.c:548
#7  0x086b1b5c in PyObject_CallFunction (callable=0xb6f69e2c,
    format=0x87e8cee "s") at Objects/abstract.c:1795
#8  0x08376d3e in getSelectedFile (name=0xbfa3721c "/house/casa2a.3ds")
    at Window.c:469
#9  0x081188bc in filesel_execute (sfile=0x8b284b8) at filesel.c:1615
#10 0x0811a093 in winqreadfilespace (sa=0x8b276b8, spacedata=0x8b284b8,
    evt=0xbfa376aa) at filesel.c:1682
#11 0x081c0a79 in scrarea_do_winhandle (area=0x8b276b8, evt=0xbfa376aa)
    at spacetypes.c:146
#12 0x08107f0f in screenmain () at editscreen.c:593
---Type <return> to continue, or q <return> to quit---
#13 0x080c9865 in main (argc=1, argv=0xbfa37874) at creator.c:697
(gdb) Quit