boto3 library is needed [1] for glance_store and didn't installed yet
since [2] adds s3 support back. this change adds both binary and source
parts to install boto3 library.
1. 04e5ead7c0/setup.cfg (L76)
2. I203134837319080ead96da69048baf90086d2117
Closes-Bug: #1884259
Change-Id: I199185e24cedd2e282c53460a24aeffc83478a12
Signed-off-by: Maksim Malchuk <maksim.malchuk@gmail.com>