Modify Makefile to ignore the doc directory. References #4521
Modify Makefile to ignore the doc directory. References #4521

adamLange/moose,jessecarterMOOSE/moose,jhbradley/moose,kasra83/moose,stimpsonsg/moose,andrsd/moose,liuwenf/moose,YaqiWang/moose,lindsayad/moose,katyhuff/moose,mellis13/moose,milljm/moose,harterj/moose,milljm/moose,stimpsonsg/moose,danielru/moose,waxmanr/moose,stimpsonsg/moose,harterj/moose,bwspenc/moose,roystgnr/moose,permcody/moose,jessecarterMOOSE/moose,markr622/moose,harterj/moose,jhbradley/moose,jessecarterMOOSE/moose,bwspenc/moose,wgapl/moose,stimpsonsg/moose,Chuban/moose,friedmud/moose,SudiptaBiswas/moose,katyhuff/moose,joshua-cogliati-inl/moose,wgapl/moose,nuclear-wizard/moose,apc-llc/moose,jasondhales/moose,idaholab/moose,jiangwen84/moose,YaqiWang/moose,nuclear-wizard/moose,yipenggao/moose,idaholab/moose,danielru/moose,giopastor/moose,jiangwen84/moose,roystgnr/moose,andrsd/moose,lindsayad/moose,xy515258/moose,permcody/moose,dschwen/moose,milljm/moose,Chuban/moose,liuwenf/moose,jiangwen84/moose,markr622/moose,joshua-cogliati-inl/moose,wgapl/moose,friedmud/moose,waxmanr/moose,giopastor/moose,lindsayad/moose,bwspenc/moose,roystgnr/moose,mellis13/moose,liuwenf/moose,roystgnr/moose,jessecarterMOOSE/moose,apc-llc/moose,raghavaggarwal/moose,waxmanr/moose,jbair34/moose,capitalaslash/moose,jasondhales/moose,dschwen/moose,jhbradley/moose,mellis13/moose,yipenggao/moose,raghavaggarwal/moose,andrsd/moose,bwspenc/moose,lindsayad/moose,dschwen/moose,jbair34/moose,idaholab/moose,jhbradley/moose,SudiptaBiswas/moose,SudiptaBiswas/moose,jasondhales/moose,YaqiWang/moose,giopastor/moose,dschwen/moose,sapitts/moose,jiangwen84/moose,backmari/moose,wgapl/moose,laagesen/moose,sapitts/moose,raghavaggarwal/moose,kasra83/moose,capitalaslash/moose,katyhuff/moose,sapitts/moose,jinmm1992/moose,giopastor/moose,yipenggao/moose,raghavaggarwal/moose,adamLange/moose,jinmm1992/moose,katyhuff/moose,mellis13/moose,SudiptaBiswas/moose,danielru/moose,nuclear-wizard/moose,joshua-cogliati-inl/moose,andrsd/moose,danielru/moose,capitalaslash/moose,laagesen/moose,roystgnr/moose,capitalaslash/moose,waxmanr/moose,backmari/moose,idaholab/moose,roystgnr/moose,apc-llc/moose,andrsd/moose,jessecarterMOOSE/moose,roystgnr/moose,bwspenc/moose,sapitts/moose,friedmud/moose,joshua-cogliati-inl/moose,Chuban/moose,permcody/moose,jbair34/moose,xy515258/moose,lindsayad/moose,milljm/moose,jinmm1992/moose,markr622/moose,friedmud/moose,SudiptaBiswas/moose,laagesen/moose,xy515258/moose,dschwen/moose,laagesen/moose,backmari/moose,yipenggao/moose,laagesen/moose,markr622/moose,liuwenf/moose,xy515258/moose,YaqiWang/moose,harterj/moose,jbair34/moose,permcody/moose,kasra83/moose,kasra83/moose,liuwenf/moose,jasondhales/moose,sapitts/moose,nuclear-wizard/moose,jinmm1992/moose,Chuban/moose,harterj/moose,milljm/moose,backmari/moose,idaholab/moose,apc-llc/moose,liuwenf/moose,adamLange/moose,adamLange/moose