Set glance protocol and port as Heat configurable

Set glance protocol and port as Heat configurable

This change is to set the glance protocol and port as
configurable via the Heat template. Presently the port is
hard-coded in the elements nova.conf file, and the protocol
is assumed as being the default (http).

This change will allow the glance_api_servers
to be set (in nova.conf) using the constituent parts:
    glance_protocol://glance_host:glance_port

Change to nova.conf to read this value is:
    Idccc0d60c9f6b17a853c6de1bbea64bfc7e028b2

Default port value is set to the nova default(9292) which is
currently hard-coded in the elements nova.conf file.
Default protocol value is set to the nova default(http).

Change-Id: I3c7218292797c62c36e2aaab4f325bf053ef140b