Add git lfs pull to moosedocs script
Add git lfs pull to moosedocs script

(refs #6699)

liuwenf/moose,SudiptaBiswas/moose,Chuban/moose,Chuban/moose,milljm/moose,nuclear-wizard/moose,idaholab/moose,jessecarterMOOSE/moose,dschwen/moose,sapitts/moose,permcody/moose,yipenggao/moose,bwspenc/moose,idaholab/moose,permcody/moose,YaqiWang/moose,liuwenf/moose,andrsd/moose,friedmud/moose,harterj/moose,milljm/moose,harterj/moose,andrsd/moose,SudiptaBiswas/moose,bwspenc/moose,dschwen/moose,backmari/moose,sapitts/moose,andrsd/moose,jessecarterMOOSE/moose,andrsd/moose,permcody/moose,friedmud/moose,dschwen/moose,yipenggao/moose,nuclear-wizard/moose,friedmud/moose,sapitts/moose,SudiptaBiswas/moose,laagesen/moose,YaqiWang/moose,sapitts/moose,permcody/moose,liuwenf/moose,jessecarterMOOSE/moose,stimpsonsg/moose,stimpsonsg/moose,nuclear-wizard/moose,bwspenc/moose,lindsayad/moose,liuwenf/moose,backmari/moose,bwspenc/moose,nuclear-wizard/moose,bwspenc/moose,YaqiWang/moose,friedmud/moose,Chuban/moose,laagesen/moose,yipenggao/moose,milljm/moose,idaholab/moose,harterj/moose,harterj/moose,lindsayad/moose,stimpsonsg/moose,stimpsonsg/moose,dschwen/moose,idaholab/moose,liuwenf/moose,laagesen/moose,laagesen/moose,backmari/moose,SudiptaBiswas/moose,milljm/moose,Chuban/moose,laagesen/moose,idaholab/moose,YaqiWang/moose,jessecarterMOOSE/moose,yipenggao/moose,lindsayad/moose,harterj/moose,backmari/moose,jessecarterMOOSE/moose,liuwenf/moose,milljm/moose,lindsayad/moose,dschwen/moose,SudiptaBiswas/moose,lindsayad/moose,andrsd/moose,sapitts/moose