Sync oslo/common/excutils
Sync oslo/common/excutils

Sync commits:
  6d0a6c3083218cdac52758a8b6aac6b03402c658
  8b2b0b743e84ceed7841cf470afed6a5da8e1d07
  fcf517d72cb81f972fad20caa9ff0341e9b4aa9c
  33a2cee6a690ecfdb2cecfe8f01b0b1dacb5bd17

Change-Id: I4f12aecf558baf0004ceed65f55520850534b73c

Tan0/ironic,Tehsmash/ironic,bacaldwell/ironic,ionutbalutoiu/ironic,naterh/ironic,debayanray/ironic_backup,ionutbalutoiu/ironic,NaohiroTamura/ironic,SauloAislan/ironic,froyobin/ironic,rackerlabs/ironic,redhat-openstack/ironic,dims/ironic,pshchelo/ironic,dims/ironic,NaohiroTamura/ironic,bacaldwell/ironic,openstack/ironic,hpproliant/ironic,SauloAislan/ironic,pshchelo/ironic,ramineni/myironic,supermari0/ironic,devananda/ironic,openstack/ironic,rdo-management/ironic,faizan-barmawer/openstack_ironic,naototty/vagrant-lxc-ironic,naototty/vagrant-lxc-ironic