autorun: place perl script _before_ generation

Otherwise we try to generate the configure/Makefile.in stuff and it
complains about filelist.mk not existing

Change-Id: I3742e5ffb6700474816b23e174862ef1b6a2582e
Reviewed-on: http://review.couchbase.org/36526
Reviewed-by: Mark Nunberg <mnunberg@haskalah.org>
Tested-by: Mark Nunberg <mnunberg@haskalah.org>