Sync excutils from oslo

In order to fix undesired error logs in Neutron (bug 1288188)
fixed save_and_reraise_exception() should be synced from oslo.
Oslo commit: 33a2cee6a690ecfdb2cecfe8f01b0b1dacb5bd17

Also sync gettextutils module as excutils depends on it
Latest commit in oslo: fd33d1eaa039913d8c82b94c511a3eab0c3d5789

Closes-Bug: #1294537
Related-Bug: #1288188
Change-Id: I62ab3e4e22aa000f3a8d1be26ef9e1cfb1714959
Merge "Sync excutils from oslo"