Added instructions to make sure correct branch is used when building usersguide
Added instructions to make sure correct branch is used when building usersguide

Ticket: 891

minesense/VisTrails,VisTrails/VisTrails,VisTrails/VisTrails,minesense/VisTrails,hjanime/VisTrails,Nikea/VisTrails,VisTrails/VisTrails,hjanime/VisTrails,celiafish/VisTrails,celiafish/VisTrails,Nikea/VisTrails,minesense/VisTrails,VisTrails/VisTrails,celiafish/VisTrails,VisTrails/VisTrails,hjanime/VisTrails,minesense/VisTrails,hjanime/VisTrails,Nikea/VisTrails,celiafish/VisTrails,hjanime/VisTrails,minesense/VisTrails,Nikea/VisTrails