Remove tools/glance-jeos-add-from-github.sh

glance-jeos-add-from-github.sh has not been edited since 2012-08-20, and
its image links have been broken (according to Google cache) for a
minimum of 9 months.

The functionality of the script seems to be superceded by the
handy-dandy diskimage-builder tool.

See http://docs.openstack.org/developer/heat/getting_started/jeos_building.html
for more info about diskimage-builder workflow.

Change-Id: I99880f1cca4af84fa7193d749a7c8f6957bb0b78
Partial-Bug: 1338066
Merge "Remove tools/glance-jeos-add-from-github.sh"