Bug 721667 - Accelerator key map loaded from one file and saved

to a different one which is ignored

So don't save it if using MAC_INTEGRATION. Changing accels on the
fly doesn't work with Mac menus anyway.

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23679 57a11ea4-9604-0410-9ed3-97b8803252fd