Fixed the Glance add_image parser for new client

The python-glanceclient (glance) was updated to not report back
on the id of an uploaded image with the v2 API [1].  This broke
the parser for the glance_image provider. This change first checks
for the previous behavior (for performance and backwards
compatability), and failing that parses the results table and
pulls the id (if it exits) out of the results.

The new parse_table method was made to be generic so that any result
from the glance client could be parsed into an array of maps.

[1]
https://github.com/openstack/python-glanceclient/search?q=Added+new+image+with+ID&ref=cmdform

Change-Id: If7b5445c6f51d886427248827a73cc16b5a2e488
Merge "Fixed the Glance add_image parser for new client"