Tree corruption when all entries are deleted

[aled]

Copied from sourceforge help forum:

Just for testing, I make an RTree with at least one element per node, and at most two elements per node. I add three items to it, remove them all, and try to add them again. The program crashes during the last of the aforementioned steps, upon the first attempt to add one of the items. As reported above, the root node is at level 2, and the tree has height 2, when the tree is empty. This seems to be the problem. It seems to be necessary to completely empty the tree in order to put it in the corrupt state. This differs from the above report, wherein it is said that the problem occurs after 100 items were added and 60-80 were removed. I tried adding 3001 and removing 3000 and there was no corruption. But removing the last item causes trouble.

[aled]

Found a bug triggered by deletion of last entry, though possibly not the same bug as described here. Committed in acfc81.