Fix to allow 'swapping' items from access point by delaying take from network until on_take

[ZenonSeth]

In response to bug reported on ContentDB

To reproduce:

• Create a network, with some storage, place some items <10 count each
• Make sure you have full stack (99) of items in your inventory
• Using an access point, take a stack of <10 items from network, but drag it onto one full (99 size) stack in your local inventory

Bug was that this caused items to be erased.

After fix, there should be no longer erased items - it does not duplicate or erase items, though the behaviour is weird due to minetest swapping mechanics.