Fix crash when no UAS
Fix crash when no UAS

Fixes Issue #1162

remspoor/qgroundcontrol,caoxiongkun/qgroundcontrol,ethz-asl/qgc_asl,CornerOfSkyline/qgroundcontrol,devbharat/qgroundcontrol,kd0aij/qgroundcontrol,kd0aij/qgroundcontrol,mihadyuk/qgroundcontrol,ethz-asl/qgc_asl,remspoor/qgroundcontrol,scott-eddy/qgroundcontrol,Hunter522/qgroundcontrol,remspoor/qgroundcontrol,scott-eddy/qgroundcontrol,LIKAIMO/qgroundcontrol,cfelipesouza/qgroundcontrol,CornerOfSkyline/qgroundcontrol,RedoXyde/PX4_qGCS,fizzaly/qgroundcontrol,greenoaktree/qgroundcontrol,LIKAIMO/qgroundcontrol,UAVenture/qgroundcontrol,devbharat/qgroundcontrol,jy723/qgroundcontrol,nado1688/qgroundcontrol,UAVenture/qgroundcontrol,caoxiongkun/qgroundcontrol,ethz-asl/qgc_asl,mihadyuk/qgroundcontrol,RedoXyde/PX4_qGCS,hejunbok/qgroundcontrol,jy723/qgroundcontrol,LIKAIMO/qgroundcontrol,cfelipesouza/qgroundcontrol,jy723/qgroundcontrol,cfelipesouza/qgroundcontrol,TheIronBorn/qgroundcontrol,kd0aij/qgroundcontrol,devbharat/qgroundcontrol,caoxiongkun/qgroundcontrol,hejunbok/qgroundcontrol,hejunbok/qgroundcontrol,cfelipesouza/qgroundcontrol,RedoXyde/PX4_qGCS,nado1688/qgroundcontrol,catch-twenty-two/qgroundcontrol,caoxiongkun/qgroundcontrol,UAVenture/qgroundcontrol,remspoor/qgroundcontrol,nado1688/qgroundcontrol,scott-eddy/qgroundcontrol,greenoaktree/qgroundcontrol,BMP-TECH/qgroundcontrol,TheIronBorn/qgroundcontrol,devbharat/qgroundcontrol,LIKAIMO/qgroundcontrol,kd0aij/qgroundcontrol,mihadyuk/qgroundcontrol,jy723/qgroundcontrol,iidioter/qgroundcontrol,hejunbok/qgroundcontrol,CornerOfSkyline/qgroundcontrol,fizzaly/qgroundcontrol,iidioter/qgroundcontrol,ethz-asl/qgc_asl,Hunter522/qgroundcontrol,dagoodma/qgroundcontrol,CornerOfSkyline/qgroundcontrol,TheIronBorn/qgroundcontrol,fizzaly/qgroundcontrol,catch-twenty-two/qgroundcontrol,remspoor/qgroundcontrol,BMP-TECH/qgroundcontrol,RedoXyde/PX4_qGCS,iidioter/qgroundcontrol,iidioter/qgroundcontrol,BMP-TECH/qgroundcontrol,nado1688/qgroundcontrol,LIKAIMO/qgroundcontrol,Hunter522/qgroundcontrol,greenoaktree/qgroundcontrol,UAVenture/qgroundcontrol,nado1688/qgroundcontrol,fizzaly/qgroundcontrol,dagoodma/qgroundcontrol,kd0aij/qgroundcontrol,mihadyuk/qgroundcontrol,mihadyuk/qgroundcontrol,Hunter522/qgroundcontrol,UAVenture/qgroundcontrol,Hunter522/qgroundcontrol,devbharat/qgroundcontrol,Hunter522/qgroundcontrol,hejunbok/qgroundcontrol,BMP-TECH/qgroundcontrol,catch-twenty-two/qgroundcontrol,fizzaly/qgroundcontrol,scott-eddy/qgroundcontrol,greenoaktree/qgroundcontrol,caoxiongkun/qgroundcontrol,RedoXyde/PX4_qGCS,scott-eddy/qgroundcontrol,mihadyuk/qgroundcontrol,cfelipesouza/qgroundcontrol,dagoodma/qgroundcontrol,CornerOfSkyline/qgroundcontrol,LIKAIMO/qgroundcontrol,TheIronBorn/qgroundcontrol,TheIronBorn/qgroundcontrol,catch-twenty-two/qgroundcontrol,iidioter/qgroundcontrol,dagoodma/qgroundcontrol,RedoXyde/PX4_qGCS,hejunbok/qgroundcontrol,dagoodma/qgroundcontrol,caoxiongkun/qgroundcontrol,iidioter/qgroundcontrol,jy723/qgroundcontrol,kd0aij/qgroundcontrol,BMP-TECH/qgroundcontrol,cfelipesouza/qgroundcontrol,BMP-TECH/qgroundcontrol,dagoodma/qgroundcontrol,catch-twenty-two/qgroundcontrol,scott-eddy/qgroundcontrol,CornerOfSkyline/qgroundcontrol,jy723/qgroundcontrol,catch-twenty-two/qgroundcontrol,devbharat/qgroundcontrol,nado1688/qgroundcontrol,fizzaly/qgroundcontrol,greenoaktree/qgroundcontrol,ethz-asl/qgc_asl,UAVenture/qgroundcontrol,remspoor/qgroundcontrol,TheIronBorn/qgroundcontrol,greenoaktree/qgroundcontrol