PATCH: Fix kernel32 LocalUnlock winetest failure

Created an attachment (id=5669)
See ticket description.

[KERNEL32]
The subtle difference between LocalUnlock and GlobalUnlock, is, that the former will return FALSE and set ERROR_NOT_LOCKED on LMEM_FIXED allocations. So, copy-paste GlobalUnlock's implementation, and modify it's behaviour.

Fixes 1 kernel32:heap winetest failure:
heap.c:389: Test failed: Expected 0, got 1

For more information, see MSDN:
LocalUnlock: http://msdn.microsoft.com/en-us/library/aa366747(v=vs.85).aspx
GlobalUnlock: http://msdn.microsoft.com/en-us/library/aa366595(v=vs.85).aspx
The difference is in the remarks section.

The modified code section is in the first if().