Fix build script if build target doesn't exist - close #2086
Fix build script if build target doesn't exist - close #2086

Script now handles this case and also handles a failing rm correctly.
'&&' caused failing rm to not exit the script

sbauer322/LightTable,rundis/LightTable,sbauer322/LightTable,kenny-evitt/LightTable,LightTable/LightTable,LightTable/LightTable,bruno-oliveira/LightTable,rundis/LightTable,bruno-oliveira/LightTable,Bost/LightTable,bruno-oliveira/LightTable,Bost/LightTable,rundis/LightTable,sbauer322/LightTable,LightTable/LightTable,Bost/LightTable,kenny-evitt/LightTable,kenny-evitt/LightTable