Added shutdown hook to STC to print summary even when interrupted by user.
Added shutdown hook to STC to print summary even when interrupted by user.

Change-Id: I2ddb0d46ddfd776101a27ea76fe5ae34d28ddded

VinodKumarS-Huawei/ietf96yang,oeeagle/onos,oplinkoms/onos,oplinkoms/onos,maheshraju-Huawei/actn,planoAccess/clonedONOS,oeeagle/onos,packet-tracker/onos,maheshraju-Huawei/actn,LorenzReinhart/ONOSnew,y-higuchi/onos,donNewtonAlpha/onos,osinstom/onos,maheshraju-Huawei/actn,oplinkoms/onos,Shashikanth-Huawei/bmp,y-higuchi/onos,castroflavio/onos,gkatsikas/onos,gkatsikas/onos,mengmoya/onos,y-higuchi/onos,mengmoya/onos,oeeagle/onos,chenxiuyang/onos,gkatsikas/onos,kuujo/onos,Shashikanth-Huawei/bmp,kkkane/ONOS,sonu283304/onos,planoAccess/clonedONOS,osinstom/onos,zsh2938/onos,sonu283304/onos,opennetworkinglab/onos,kkkane/ONOS,kkkane/ONOS,sdnwiselab/onos,opennetworkinglab/onos,chenxiuyang/onos,gkatsikas/onos,chenxiuyang/onos,maheshraju-Huawei/actn,LorenzReinhart/ONOSnew,osinstom/onos,sdnwiselab/onos,VinodKumarS-Huawei/ietf96yang,packet-tracker/onos,kuujo/onos,oplinkoms/onos,zsh2938/onos,sdnwiselab/onos,packet-tracker/onos,oeeagle/onos,VinodKumarS-Huawei/ietf96yang,castroflavio/onos,zsh2938/onos,opennetworkinglab/onos,mengmoya/onos,kuujo/onos,kuujo/onos,kuujo/onos,lsinfo3/onos,kkkane/ONOS,mengmoya/onos,sdnwiselab/onos,sdnwiselab/onos,opennetworkinglab/onos,planoAccess/clonedONOS,opennetworkinglab/onos,sonu283304/onos,VinodKumarS-Huawei/ietf96yang,Shashikanth-Huawei/bmp,y-higuchi/onos,Shashikanth-Huawei/bmp,donNewtonAlpha/onos,gkatsikas/onos,sonu283304/onos,kuujo/onos,VinodKumarS-Huawei/ietf96yang,maheshraju-Huawei/actn,chenxiuyang/onos,castroflavio/onos,sdnwiselab/onos,lsinfo3/onos,kuujo/onos,zsh2938/onos,LorenzReinhart/ONOSnew,gkatsikas/onos,LorenzReinhart/ONOSnew,lsinfo3/onos,osinstom/onos,donNewtonAlpha/onos,mengmoya/onos,packet-tracker/onos,oplinkoms/onos,planoAccess/clonedONOS,lsinfo3/onos,castroflavio/onos,donNewtonAlpha/onos,y-higuchi/onos,opennetworkinglab/onos,oplinkoms/onos,oplinkoms/onos,donNewtonAlpha/onos,Shashikanth-Huawei/bmp,LorenzReinhart/ONOSnew,osinstom/onos