Since REMOTE SERVICE INTERFACE has default value to 'public',
it doesn't make sense to have validation for the same.
Removing this validation and added few missing tests for
glance-download import method
Conflicts:
glanceclient/tests/unit/v2/test_shell_v2.py
NOTE: Resolved conflicts caused due to I1d8c69acd5d61fdc426469cd87d1ace81871e60f
Closes-Bug: #2051761
Change-Id: I89adf23aac5db4f2c46379546def2f71d7c8e163
(cherry picked from commit 3c5dd2381f)
(cherry picked from commit d739d313a7)
d94f563363