[TASK] Remove init code from showpic.php

showpic.php is called through eiD for several versions now,
so the initialization code can be removed.

Change-Id: I2f428e8bbf678dde3a20c91adfb536ee61a65aa8
Resolves: #36865
Releases: 6.0
Reviewed-on: http://review.typo3.org/11016
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn