Sync oslo/common/excutils

Sync commits:
  6d0a6c3083218cdac52758a8b6aac6b03402c658
  8b2b0b743e84ceed7841cf470afed6a5da8e1d07
  fcf517d72cb81f972fad20caa9ff0341e9b4aa9c
  33a2cee6a690ecfdb2cecfe8f01b0b1dacb5bd17

Change-Id: I4f12aecf558baf0004ceed65f55520850534b73c
Merge "Sync oslo/common/excutils"