Fix initial loading of a route with an invalid session
Fix initial loading of a route with an invalid session

no issue
- if the session is "authenticated" but is invalid, the initial load of the app would fail. It could be replicated by:
	1. Authenticating in a running ghost instance
	2. Stopping ghost
	3. Deleting the database
	4. Re-starting ghost
	5. Closing the browser
	6. Re-opening the browser and visiting http://localhost:2368/ghost
- this fix stores the `transition` object for the duration of the initial load so that `sessionInvalidated` method can trigger actions before the transition has finished

Kikobeats/Ghost,tidyui/Ghost,pollbox/ghostblog,TryGhost/Ghost,sebgie/Ghost,JohnONolan/Ghost,ngosinafrica/SiteForNGOs,chevex/undoctrinate,ngosinafrica/SiteForNGOs,Elektro1776/javaPress,letsjustfixit/Ghost,lf2941270/Ghost,Gargol/Ghost,AlexKVal/Ghost,stridespace/Ghost,cwonrails/Ghost,NovaDevelopGroup/Academy,Kikobeats/Ghost,sunh3/Ghost,vainglori0us/urban-fortnight,bosung90/Ghost,lf2941270/Ghost,Elektro1776/javaPress,novaugust/Ghost,NovaDevelopGroup/Academy,petersucks/blog,kevinansfield/Ghost,hnarayanan/narayanan.co,lukekhamilton/Ghost,sebgie/Ghost,BlueHatbRit/Ghost,JohnONolan/Ghost,AlexKVal/Ghost,GroupxDev/javaPress,ManRueda/manrueda-blog,daimaqiao/Ghost-Bridge,ignasbernotas/nullifer,acburdine/Ghost,leonli/ghost,novaugust/Ghost,dbalders/Ghost,bosung90/Ghost,olsio/Ghost,jomahoney/Ghost,leninhasda/Ghost,letsjustfixit/Ghost,JohnONolan/Ghost,olsio/Ghost,singular78/Ghost,daimaqiao/Ghost-Bridge,bitjson/Ghost,TryGhost/Ghost,vainglori0us/urban-fortnight,e10/Ghost,kevinansfield/Ghost,leonli/ghost,ManRueda/manrueda-blog,hnarayanan/narayanan.co,mohanambati/Ghost,pollbox/ghostblog,janvt/Ghost,petersucks/blog,vainglori0us/urban-fortnight,tidyui/Ghost,letsjustfixit/Ghost,adam-paterson/blog,acburdine/Ghost,jorgegilmoreira/ghost,cwonrails/Ghost,sebgie/Ghost,stridespace/Ghost,dbalders/Ghost,leninhasda/Ghost,adam-paterson/blog,Elektro1776/javaPress,kevinansfield/Ghost,MadeOnMars/Ghost,klinker-apps/ghost,lukekhamilton/Ghost,daimaqiao/Ghost-Bridge,rizkyario/Ghost,sunh3/Ghost,NovaDevelopGroup/Academy,dbalders/Ghost,ballPointPenguin/Ghost,ivantedja/ghost,ErisDS/Ghost,singular78/Ghost,TryGhost/Ghost,bitjson/Ghost,disordinary/Ghost,jorgegilmoreira/ghost,ignasbernotas/nullifer,e10/Ghost,jomahoney/Ghost,mohanambati/Ghost,ErisDS/Ghost,GroupxDev/javaPress,jorgegilmoreira/ghost,javorszky/Ghost,SkynetInc/steam,MadeOnMars/Ghost,obsoleted/Ghost,janvt/Ghost,ManRueda/manrueda-blog,Kikobeats/Ghost,ballPointPenguin/Ghost,cwonrails/Ghost,ErisDS/Ghost,leonli/ghost,singular78/Ghost,BlueHatbRit/Ghost,stridespace/Ghost,klinker-apps/ghost,javorszky/Ghost,kaychaks/kaushikc.org,SkynetInc/steam,mohanambati/Ghost,kaychaks/kaushikc.org,acburdine/Ghost,disordinary/Ghost,Gargol/Ghost,rizkyario/Ghost,obsoleted/Ghost,rizkyario/Ghost,GroupxDev/javaPress,novaugust/Ghost