Removed docs build for Travis-CI.
Removed docs build for Travis-CI.

decvalts/landlab,ManuSchmi88/landlab,RondaStrauch/landlab,csherwood-usgs/landlab,amandersillinois/landlab,laijingtao/landlab,RondaStrauch/landlab,RondaStrauch/landlab,ManuSchmi88/landlab,Carralex/landlab,landlab/landlab,landlab/landlab,cmshobe/landlab,cmshobe/landlab,landlab/landlab,csherwood-usgs/landlab,Carralex/landlab,Carralex/landlab,laijingtao/landlab,decvalts/landlab,ManuSchmi88/landlab,cmshobe/landlab,SiccarPoint/landlab,amandersillinois/landlab,SiccarPoint/landlab