Fix minor typos in install doc.
Fix minor typos in install doc.

dougkerr/surveillance,NeighborhoodGuard/communityview,NeighborhoodGuard/communityview,NeighborhoodGuard/communityview,JesperJurcenoks/communityview,NeighborhoodGuard/communityview,dougkerr/surveillance,NeighborhoodGuard/communityview,JesperJurcenoks/communityview,dougkerr/surveillance,dougkerr/surveillance,dougkerr/surveillance