Improvements to build-all-docker-images script
Improvements to build-all-docker-images script

Trap interrupt signal so that the build-all-docker-images script is
stopped on Ctrl-C, and not only the current build.

Additionally, the script now prints a summary of changes on exit.

Change-Id: I3f6ef97d776c7799c73bc709070d97d37406637a

toby82/kolla,HackToday/kolla,chenzhiwei/kolla,chenzhiwei/kolla,stackforge/kolla,GalenMa/kolla,stackforge/kolla,rajalokan/kolla,tonyli71/kolla,LoHChina/kolla,fdumpling/kolla,chenzhiwei/kolla,tonyli71/kolla,invenfantasy/kolla,dardelean/kolla-ansible,intel-onp/kolla,mandre/kolla,nihilifer/kolla,bdastur/kolla,jakedahn/kolla,toby82/kolla,nihilifer/kolla,HackToday/kolla,limamauricio/mykolla,thetrav/kolla,brk3/kolla,mandre/kolla,coolsvap/kolla,meticulo3366/kolla,negronjl/kolla,fdumpling/kolla,coolsvap/kolla,fdumpling/kolla,rajalokan/kolla,openstack/kolla,negronjl/kolla,mandre/kolla,openstack/kolla,LoHChina/kolla,dardelean/kolla-ansible,jakedahn/kolla,GalenMa/kolla,dardelean/kolla-ansible,rajalokan/kolla,brk3/kolla,bdastur/kolla,HackToday/kolla,rahulunair/kolla,jakedahn/kolla,LoHChina/kolla,coolsvap/kolla,intel-onp/kolla,limamauricio/mykolla,rahulunair/kolla,mrangana/kolla,stackforge/kolla,thetrav/kolla,invenfantasy/kolla,mrangana/kolla,limamauricio/mykolla,meticulo3366/kolla,negronjl/kolla,toby82/kolla,invenfantasy/kolla