fix error from basename when using source to run hack/lib/init.sh
fix error from basename when using source to run hack/lib/init.sh

The example in CONTRIBUTING.adoc uses 'source' to run hack/lib/init.sh and
prints an error on an invalid basename command due to $0 returning "-bash".

luciddreamz/origin,jsafrane/origin,childsb/origin,nak3/origin,pecameron/origin,jeremyeder/origin,openshift/origin,deads2k/origin,sallyom/origin,linzhaoming/origin,tnozicka/origin,mdshuai/origin,sferich888/origin,gabemontero/origin,spadgett/origin,markllama/origin,liangxia/origin,nak3/origin,aveshagarwal/origin,tnozicka/origin,Miciah/origin,coreydaley/origin,akram/origin,mfojtik/origin,hroyrh/origin,bparees/origin,mdshuai/origin,bparees/origin,pweil-/origin,imcsk8/origin,kargakis/origin,aveshagarwal/origin,ironcladlou/origin,imcsk8/origin,linzhaoming/origin,luciddreamz/origin,mdshuai/origin,deads2k/origin,JacobTanenbaum/origin,liangxia/origin,luciddreamz/origin,ramr/origin,kargakis/origin,mkumatag/origin,markllama/origin,childsb/origin,nak3/origin,tnozicka/origin,ingvagabund/origin,sjug/origin,soltysh/origin,mdshuai/origin,JacobTanenbaum/origin,hroyrh/origin,csrwng/origin,imcsk8/origin,sdminonne/origin,jeremyeder/origin,deads2k/origin,ingvagabund/origin,gabemontero/origin,soltysh/origin,jeremyeder/origin,JacobTanenbaum/origin,linzhaoming/origin,luciddreamz/origin,liangxia/origin,dinhxuanvu/origin,jsafrane/origin,coreydaley/origin,sdminonne/origin,ramr/origin,ingvagabund/origin,childsb/origin,mahak/origin,openshift/origin,enj/origin,sdminonne/origin,sjug/origin,mahak/origin,kargakis/origin,spadgett/origin,dinhxuanvu/origin,tnozicka/origin,mkumatag/origin,jim-minter/origin,luciddreamz/origin,dinhxuanvu/origin,childsb/origin,Miciah/origin,jeremyeder/origin,linzhaoming/origin,ramr/origin,jsafrane/origin,csrwng/origin,openshift/origin,spadgett/origin,gabemontero/origin,anpingli/origin,jeremyeder/origin,mdshuai/origin,akram/origin,enj/origin,kargakis/origin,aveshagarwal/origin,markllama/origin,bparees/origin,mfojtik/origin,markllama/origin,aveshagarwal/origin,csrwng/origin,tnozicka/origin,aveshagarwal/origin,kargakis/origin,sferich888/origin,anpingli/origin,sallyom/origin,sferich888/origin,liangxia/origin,mdshuai/origin,ironcladlou/origin,pecameron/origin,dinhxuanvu/origin,linzhaoming/origin,pweil-/origin,mfojtik/origin,liangxia/origin,markllama/origin,ironcladlou/origin,markllama/origin,jim-minter/origin,liangxia/origin,ramr/origin,mkumatag/origin,xiuwang/origin,luciddreamz/origin,enj/origin,jim-minter/origin,hroyrh/origin,spadgett/origin,xiuwang/origin,spadgett/origin,tnozicka/origin,mahak/origin,pecameron/origin,ramr/origin,imcsk8/origin,xiuwang/origin,childsb/origin,pweil-/origin,imcsk8/origin,childsb/origin,sallyom/origin,anpingli/origin,akram/origin,kargakis/origin,dinhxuanvu/origin,Miciah/origin,coreydaley/origin,imcsk8/origin,soltysh/origin,sjug/origin