Fixes `ln` command in Linux installation guide.
Fixes `ln` command in Linux installation guide.

* sudo tar xvjf phantomjs-1.6.0-linux-*-dynamic.tar.gz -C /usr/local extracts
  to the /usr/local/phantomjs-1.6.0-linux-x86_64-dynamic directory. Given that,
  the `ln` command needs to be adjusted to work correctly.

Nuru/poltergeist,SolarCS/poltergeist,martijnrusschen/poltergeist,afn/poltergeist,exchangegroup/poltergeist,bigloser/poltergeist,TalentBox/poltergeist,irfanah/poltergeist,ryansch/poltergeist,ryansch/poltergeist,irfanah/poltergeist,dv/poltergeist,roblander/poltergeist,OneTechLP/Poltergeist,mattrw89/poltergeist,TalentBox/poltergeist,martijnrusschen/poltergeist,jjoos/poltergeist,vietch2612/poltergeist,tribble/poltergeist,exchangegroup/poltergeist,SolarCS/poltergeist,SolarCS/poltergeist,bigloser/poltergeist,roblander/poltergeist,thomasrogers03/poltergeist,vietch2612/poltergeist,Nuru/poltergeist,rafaelfranca/poltergeist,SolarCS/poltergeist,airservice/poltergeist,irfanah/poltergeist,exchangegroup/poltergeist,geminiyellow/poltergeist,jjoos/poltergeist,roblander/poltergeist,teampoltergeist/poltergeist,geminiyellow/poltergeist,dv/poltergeist,ducthanh/poltergeist,jjoos/poltergeist,martijnrusschen/poltergeist,rafaelfranca/poltergeist,ryansch/poltergeist,TalentBox/poltergeist,teampoltergeist/poltergeist,teampoltergeist/poltergeist,TalentBox/poltergeist,twalpole/poltergeist,ducthanh/poltergeist,ryansch/poltergeist,Nuru/poltergeist,afn/poltergeist,dv/poltergeist,geminiyellow/poltergeist,thomasrogers03/poltergeist,tribble/poltergeist,exchangegroup/poltergeist,airservice/poltergeist,bigloser/poltergeist,afn/poltergeist,rafaelfranca/poltergeist,twalpole/poltergeist,irfanah/poltergeist,tribble/poltergeist,exviva/poltergeist,airservice/poltergeist,thomasrogers03/poltergeist,roblander/poltergeist,ducthanh/poltergeist,jjoos/poltergeist,rafaelfranca/poltergeist,twalpole/poltergeist,ducthanh/poltergeist,mattrw89/poltergeist,tribble/poltergeist,exviva/poltergeist,OneTechLP/Poltergeist,vietch2612/poltergeist,twalpole/poltergeist,mattrw89/poltergeist,Nuru/poltergeist,thomasrogers03/poltergeist,airservice/poltergeist,bigloser/poltergeist,afn/poltergeist,teampoltergeist/poltergeist,mattrw89/poltergeist,vietch2612/poltergeist,geminiyellow/poltergeist,dv/poltergeist,martijnrusschen/poltergeist,OneTechLP/Poltergeist,exviva/poltergeist