[PATCH] fix problems using scsi_id with udevstart

[PATCH] fix problems using scsi_id with udevstart

when udevstart was running we didn't set the environment and the
subsystem argument for the callouts the dev.d/ scripts.

Here is a fix, that sets that with every udevstart iteration, corrects
argv[0] to be the basename() only not the whole path  and adds a test
for invoking callouts without arguments.