commit 423df1fa
    Date:   Thu Nov 2 12:53:14 2017 +0100

        Resolves: tdf#111428 implement CellStoreEvent::swap() in ScColumn::SwapCol()

erroneously swapped also the CellStoreEvent's ScColumn* but of
course the CellStoreEvent stays at its ScColumn and is not swapped
with the CellStoreType. So swap only the mnBlkCountFormula that
CellStoreEvent::mpCol accesses.

ASAN rightly complained about heap-use-after-free.

Change-Id: Ic44fed96c49bea7365bf1200e06788860966795c