Print the reverting back to v1 to stderr
Print the reverting back to v1 to stderr

Printing to stderr to fix the download issue.

Change-Id: I2916bb100ac451378db82291855078f2b37466bd
Closes-Bug: #1488914

klmitch/python-glanceclient,openstack/python-glanceclient,openstack/python-glanceclient,klmitch/python-glanceclient