Bug 25485: Remove tiny_mce symlink during pre install of deb package

Bug 25485: Remove tiny_mce symlink during pre install of deb package

This patch removes the tiny_mce symlink before Koha package installation
using the same method that we used when we removed the YUI symlink
in 2015.

Signed-off-by: David Cook <dcook@prosentient.com.au>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Joy Nelson <joy@bywatersolutions.com>