rackup: include the value of each -I command line option in $LOAD_PATH
rackup: include the value of each -I command line option in $LOAD_PATH

`rackup -h` says '-I' can be used more than once.  However, instead of adding
each value to $LOAD_PATH, rackup would discard the value of all but the last
'-I' option.

Signed-off-by: Anurag Priyam <6e6ab5ea9cb59fe7c35d2a1fc74443577eb60635@gmail.com>

wildjcrt/rack,eins78/rack,stepri/rack,akihiro17/rack,trexnix/rack,keithduncan/rack,nmk/rack,arronmabrey/rack,liamseanbrady/rack,keepcosmos/rack,liamseanbrady/rack,davydovanton/rack,sigmavirus24/rack,stepri/rack,gfvcastro/rack,Codeman655/rack,eavgerinos/rack,Comcast/rack,evanphx/rack,gioele/rack,eavgerinos/rack,Codeman655/rack,ktheory/rack,gioele/rack,jackxxu/rack,wjordan/rack,imtayadeway/rack,wildjcrt/rack,rwz/rack,maclover7/rack,keepcosmos/rack,eavgerinos/rack,nmk/rack,wildjcrt/rack,krainboltgreene/lack,deepj/rack,fabianrbz/rack,ganmacs/rack,deepj/rack,gfvcastro/rack,laplaceliu/rack,akihiro17/rack,zjsxwc/rack,keepcosmos/rack,ngpestelos/rack,shaneog/rack,ganmacs/rack,rwz/rack,chneukirchen/rack,supzann3/rack,davidcelis/rack,jeremyf/rack,davidcelis/rack,nmk/rack,tylergannon/rack,keithduncan/rack,tricknotes/rack,rwz/rack,ktheory/rack,davydovanton/rack,chneukirchen/rack,trexnix/rack,AMekss/rack,shaneog/rack,sigmavirus24/rack,Comcast/rack,tylergannon/rack,akihiro17/rack,supzann3/rack,imtayadeway/rack,imtayadeway/rack,AMekss/rack,trexnix/rack,Eric-Guo/rack,ngpestelos/rack,deepj/rack,evanphx/rack,keithduncan/rack,stepri/rack,gioele/rack,tricknotes/rack,zjsxwc/rack,arronmabrey/rack,ganmacs/rack,rkh/rack,ngpestelos/rack,fabianrbz/rack,eins78/rack,maclover7/rack,davidcelis/rack,tylergannon/rack,arronmabrey/rack,chneukirchen/rack,gfvcastro/rack,Codeman655/rack,maclover7/rack,jeremyf/rack,Eric-Guo/rack,rkh/rack,laplaceliu/rack,zjsxwc/rack,wjordan/rack,evanphx/rack,eins78/rack,supzann3/rack,jackxxu/rack,davydovanton/rack,jeremyf/rack,wjordan/rack,fabianrbz/rack,sigmavirus24/rack,AMekss/rack,Comcast/rack,laplaceliu/rack,shaneog/rack,Eric-Guo/rack,jackxxu/rack,liamseanbrady/rack