key in btree should ignore OverflowError

[jamadden]

Currently, key in btree ignores TypeError, so this all works:

>>> import BTrees
>>> bt = BTrees.family32.II.BTree()
>>> 'abc' in bt
False
>>> bt.get('abc') is None
True

But if the key is outside the range allowed, it fails:

>>> x = 2 ** 64
>>> x in bt
OverflowError: Python int too large to convert to C long
>>>  bt.get(x)
OverflowError: Python int too large to convert to C long

For consistency, the OverflowError should be ignored in those cases too. (This would happen automatically if it was a TypeError instead of an OverflowError.) The pure-Python implementation already handles this (…by raising a TypeError, I think).

Also weird and should not raise (works in pure-Python):

>>> bt.has_key(1)
0
>>> bt.has_key('abc')
KeyError: 'abc'
>>> bt.has_key(x)
OverflowError: Python int too large to convert to C long

Confirmed this to be an issue back to 4.6. The changes in 4.3.2 were not sufficient for the overflow case.