Bug 17356: Add atomic update .perl skeleton file

Bug 17356: Add atomic update .perl skeleton file

To show devs how it should be written.

Test plan:
% cp installer/data/mysql/atomicupdate/skeleton.perl
installer/data/mysql/atomicupdate/bug_XXXXX.perl
% perl installer/data/mysql/updatedatabase.pl

You should see:
DEV atomic update: bug_xxxxx.perl
Upgrade to 16.06.00.XXX done (Bug XXXXX - description)

Signed-off-by: Liz Rea <liz@catalyst.net.nz>
Very good. I'll submit a patch for the readme to make the instructions better.

Signed-off-by: Liz Rea <liz@catalyst.net.nz>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>