[Trivial] Remove unnecessary executable privilege
[Trivial] Remove unnecessary executable privilege

glanceclient/shell.py defines a main entry, however this file cannot
be executed directly because we do not call the main function in
this file. It is actually a module which will be used by
/usr/bin/glance, hence doesn't need to be executable.

Change-Id: I8b45ac7b8b88265cfc27e5ba7201e4766d9dc276

openstack/python-glanceclient,openstack/python-glanceclient