ARM-CI : Add logging for getting the reason of unmounting issue.
ARM-CI : Add logging for getting the reason of unmounting issue.

    Recently I find unmount error frequently. (http://dotnet-ci.cloudapp.net/job/dotnet_corefx/job/master/job/linuxarmemulator_cross_debug/106/console)

    So I would take some below actions temoprarily. I think this problem is different from CoreCLR. We have to get logs when the mounting error is occurred.

    1. Re-enable the automatic checks for ARM emulator.
    2. Add logging for getting the reason of unmounting issue.

Ermiar/corefx,weltkante/corefx,mazong1123/corefx,wtgodbe/corefx,Jiayili1/corefx,alphonsekurian/corefx,nchikanov/corefx,ericstj/corefx,yizhang82/corefx,YoupHulsebos/corefx,shimingsg/corefx,Ermiar/corefx,cydhaselton/corefx,alphonsekurian/corefx,seanshpark/corefx,axelheer/corefx,mmitche/corefx,rahku/corefx,Petermarcu/corefx,dhoehna/corefx,marksmeltzer/corefx,shmao/corefx,stephenmichaelf/corefx,jlin177/corefx,richlander/corefx,dotnet-bot/corefx,axelheer/corefx,seanshpark/corefx,billwert/corefx,shmao/corefx,alphonsekurian/corefx,jlin177/corefx,JosephTremoulet/corefx,alexperovich/corefx,parjong/corefx,tijoytom/corefx,YoupHulsebos/corefx,MaggieTsang/corefx,weltkante/corefx,lggomez/corefx,MaggieTsang/corefx,nchikanov/corefx,jlin177/corefx,shimingsg/corefx,gkhanna79/corefx,the-dwyer/corefx,stone-li/corefx,lggomez/corefx,mazong1123/corefx,ericstj/corefx,DnlHarvey/corefx,rahku/corefx,mmitche/corefx,shimingsg/corefx,parjong/corefx,shimingsg/corefx,gkhanna79/corefx,wtgodbe/corefx,weltkante/corefx,cydhaselton/corefx,marksmeltzer/corefx,mazong1123/corefx,marksmeltzer/corefx,billwert/corefx,ViktorHofer/corefx,seanshpark/corefx,richlander/corefx,richlander/corefx,gkhanna79/corefx,twsouthwick/corefx,dotnet-bot/corefx,weltkante/corefx,richlander/corefx,rjxby/corefx,ravimeda/corefx,parjong/corefx,cydhaselton/corefx,rjxby/corefx,JosephTremoulet/corefx,twsouthwick/corefx,the-dwyer/corefx,krytarowski/corefx,marksmeltzer/corefx,shmao/corefx,ericstj/corefx,stone-li/corefx,ericstj/corefx,jlin177/corefx,alphonsekurian/corefx,mmitche/corefx,ptoonen/corefx,mazong1123/corefx,billwert/corefx,nbarbettini/corefx,seanshpark/corefx,the-dwyer/corefx,parjong/corefx,BrennanConroy/corefx,zhenlan/corefx,shmao/corefx,dhoehna/corefx,YoupHulsebos/corefx,twsouthwick/corefx,Petermarcu/corefx,cydhaselton/corefx,seanshpark/corefx,yizhang82/corefx,gkhanna79/corefx,tijoytom/corefx,twsouthwick/corefx,billwert/corefx,nchikanov/corefx,nbarbettini/corefx,alexperovich/corefx,DnlHarvey/corefx,rubo/corefx,ericstj/corefx,weltkante/corefx,mmitche/corefx,stone-li/corefx,rjxby/corefx,jlin177/corefx,nbarbettini/corefx,DnlHarvey/corefx,alexperovich/corefx,ptoonen/corefx,krk/corefx,richlander/corefx,mazong1123/corefx,shimingsg/corefx,Petermarcu/corefx,rubo/corefx,Ermiar/corefx,twsouthwick/corefx,Jiayili1/corefx,ericstj/corefx,lggomez/corefx,rahku/corefx,zhenlan/corefx,tijoytom/corefx,seanshpark/corefx,krytarowski/corefx,twsouthwick/corefx,krk/corefx,Petermarcu/corefx,zhenlan/corefx,mmitche/corefx,wtgodbe/corefx,Jiayili1/corefx,weltkante/corefx,dhoehna/corefx,lggomez/corefx,MaggieTsang/corefx,JosephTremoulet/corefx,gkhanna79/corefx,nchikanov/corefx,alexperovich/corefx,tijoytom/corefx,ericstj/corefx,DnlHarvey/corefx,shimingsg/corefx,ravimeda/corefx,lggomez/corefx,lggomez/corefx,YoupHulsebos/corefx,elijah6/corefx,dhoehna/corefx,krk/corefx,zhenlan/corefx,axelheer/corefx,ptoonen/corefx,nchikanov/corefx,stephenmichaelf/corefx,rjxby/corefx,nbarbettini/corefx,stephenmichaelf/corefx,Petermarcu/corefx,nchikanov/corefx,zhenlan/corefx,alphonsekurian/corefx,wtgodbe/corefx,mmitche/corefx,elijah6/corefx,elijah6/corefx,lggomez/corefx,gkhanna79/corefx,axelheer/corefx,alphonsekurian/corefx,rubo/corefx,dotnet-bot/corefx,DnlHarvey/corefx,ravimeda/corefx,yizhang82/corefx,gkhanna79/corefx,YoupHulsebos/corefx,zhenlan/corefx,wtgodbe/corefx,rahku/corefx,elijah6/corefx,the-dwyer/corefx,ptoonen/corefx,ravimeda/corefx,fgreinacher/corefx,elijah6/corefx,krytarowski/corefx,shmao/corefx,tijoytom/corefx,YoupHulsebos/corefx,Petermarcu/corefx,nbarbettini/corefx,krk/corefx,JosephTremoulet/corefx,ViktorHofer/corefx,marksmeltzer/corefx,axelheer/corefx,stephenmichaelf/corefx,mazong1123/corefx,MaggieTsang/corefx,tijoytom/corefx,richlander/corefx,krk/corefx,MaggieTsang/corefx,wtgodbe/corefx,ptoonen/corefx,marksmeltzer/corefx,nbarbettini/corefx,rubo/corefx,marksmeltzer/corefx,cydhaselton/corefx,krytarowski/corefx,mazong1123/corefx,MaggieTsang/corefx,elijah6/corefx,stephenmichaelf/corefx,mmitche/corefx,ravimeda/corefx,Ermiar/corefx,JosephTremoulet/corefx,dotnet-bot/corefx,dhoehna/corefx,alexperovich/corefx,ViktorHofer/corefx,krytarowski/corefx,rjxby/corefx,stone-li/corefx,fgreinacher/corefx,ptoonen/corefx,cydhaselton/corefx,jlin177/corefx,alphonsekurian/corefx,billwert/corefx,shimingsg/corefx,rjxby/corefx,shmao/corefx,Ermiar/corefx,krk/corefx,Jiayili1/corefx,ViktorHofer/corefx,weltkante/corefx,fgreinacher/corefx,stone-li/corefx,Jiayili1/corefx,seanshpark/corefx,ViktorHofer/corefx,cydhaselton/corefx,yizhang82/corefx,parjong/corefx,shmao/corefx,krytarowski/corefx,ravimeda/corefx,stone-li/corefx,stephenmichaelf/corefx,yizhang82/corefx,rahku/corefx,rahku/corefx,BrennanConroy/corefx,Jiayili1/corefx,ViktorHofer/corefx,parjong/corefx,alexperovich/corefx,Ermiar/corefx,billwert/corefx,parjong/corefx,ptoonen/corefx,stephenmichaelf/corefx,billwert/corefx,JosephTremoulet/corefx,DnlHarvey/corefx,ravimeda/corefx,krytarowski/corefx,DnlHarvey/corefx,YoupHulsebos/corefx,Jiayili1/corefx,JosephTremoulet/corefx,fgreinacher/corefx,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