Bug 11347 - PROG/CCSR deprecation: Remove opacsmallimage system-preference

Bug 11347 - PROG/CCSR deprecation: Remove opacsmallimage system-preference

The opacsmallimage system preference is unused in the bootstrap theme.
It can be removed now that prog and ccsr are deprecated. This patch does
so.

To test, apply the patch and run updatedatabase. Confirm that the OPAC
works properly and the preference can no longer be found.

Signed-off-by: Bernardo Gonzalez Kriegel <bgkriegel@gmail.com>
Preference removed, no koha-qa errors

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>