Bug 21783: Reindent admin/columns_settings.tt

Bug 21783: Reindent admin/columns_settings.tt

This patch reindents admin/columns_settings.tt to use four spaces
instead of two for indentation, following coding guidelines.

To test, apply the patch and compare the file to master using the -w
flag to ignore whitespace. The only changes should appear where lines
were added during indentation.

Go to Admin -> Columns settings and confirm that everything works
correctly.

Signed-off-by: Hayley Mapley <hayleymapley@catalyst.net.nz>
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>