Load VTK libraries after matplotlib's
Load VTK libraries after matplotlib's

Have Peacock load VTK libraries after matplotlib's to avoid a
missing symbol/version issue on the aging Ubuntu 14.x platform.

Closes #10643

dschwen/moose,nuclear-wizard/moose,harterj/moose,jessecarterMOOSE/moose,harterj/moose,milljm/moose,sapitts/moose,permcody/moose,lindsayad/moose,milljm/moose,YaqiWang/moose,harterj/moose,harterj/moose,nuclear-wizard/moose,andrsd/moose,laagesen/moose,sapitts/moose,milljm/moose,laagesen/moose,lindsayad/moose,idaholab/moose,jessecarterMOOSE/moose,nuclear-wizard/moose,dschwen/moose,idaholab/moose,idaholab/moose,andrsd/moose,lindsayad/moose,permcody/moose,permcody/moose,dschwen/moose,permcody/moose,sapitts/moose,bwspenc/moose,laagesen/moose,andrsd/moose,SudiptaBiswas/moose,bwspenc/moose,bwspenc/moose,idaholab/moose,lindsayad/moose,dschwen/moose,YaqiWang/moose,jessecarterMOOSE/moose,nuclear-wizard/moose,andrsd/moose,laagesen/moose,SudiptaBiswas/moose,lindsayad/moose,andrsd/moose,milljm/moose,dschwen/moose,bwspenc/moose,SudiptaBiswas/moose,YaqiWang/moose,harterj/moose,bwspenc/moose,jessecarterMOOSE/moose,YaqiWang/moose,laagesen/moose,milljm/moose,SudiptaBiswas/moose,idaholab/moose,jessecarterMOOSE/moose,sapitts/moose,SudiptaBiswas/moose,sapitts/moose