=== From our customer ===
When the tenants query the glance api searching for "current" version, its returning a 2 digit suffix (v2.10). 
Taking that version and using it to query the image list, glance returns: 300 MULTIPLE_CHOICES. This doesn't happen 1 digit suffix (ie v2.9)

=== My take on this ===
It looks like glance does not understand when we pass version 2.10 explicitly, and returns the list of available versions. 2.10 should be a valid choice.

Reproducible: Always

Steps to Reproduce:
1. curl the glance endpoint with different version
2. this will list the images, as expected, except when using the 'current' release, 2.10



Actual Results:  
=== Curl while using v2 ===

(overcloud) [stack@undercloud ~]$ curl -X GET http://10.2.0.254:9292/v2/images -H "X-Auth-Token: $(openstack token issue | awk '/ id / {print $4}')"
{"images": [{"name": "CirrOS", "disk_format": "qcow2", "container_format": "bare", "visibility": "public", "size": 21430272, "virtual_size": null, "status": "active", "checksum": "c8fc807773e5354afe61636071771906", (...truncated) "schema": "/v2/schemas/image", "stores": "default_backend"}], "first": "/v2/images", "schema": "/v2/schemas/images"}

=== Curl while using v2.9 ===
(overcloud) [stack@undercloud ~]$ curl -X GET http://10.2.0.254:9292/v2.9/images -H "X-Auth-Token: $(openstack token issue | awk '/ id / {print $4}')"
{"images": [{"name": "CirrOS", "disk_format": "qcow2", "container_format": "bare", "visibility": "public", "size": 21430272, "virtual_size": null, "status": "active", "checksum": "c8fc807773e5354afe61636071771906", (...truncated) "schema": "/v2/schemas/image", "stores": "default_backend"}], "first": "/v2/images", "schema": "/v2/schemas/images"}

=== Curl while using 2.10 ===
(overcloud) [stack@undercloud ~]$ curl -X GET http://10.2.0.254:9292/v2.10/images -H "X-Auth-Token: $(openstack token issue | awk '/ id / {print $4}')"
{"versions": [{"id": "v2.10", "status": "CURRENT", "links": [{"rel": "self", "href": "http://10.2.0.254:9292/v2/"}]}, {"id": "v2.9", "status": "SUPPORTED", "links": [{"rel": "self", "href": "http://10.2.0.254:9292/v2/"}]}, {"id": "v2.8", "status": "SUPPORTED", "links": [{"rel": "self", "href": "http://10.2.0.254:9292/v2/"}]}, {"id": "v2.7", "status": "SUPPORTED", "links": [{"rel": "self", "href": "http://10.2.0.254:9292/v2/"}]}, {"id": "v2.6", "status": "SUPPORTED", "links": [{"rel": "self", "href": "http://10.2.0.254:9292/v2/"}]}, {"id": "v2.5", "status": "SUPPORTED", "links": [{"rel": "self", "href": "http://10.2.0.254:9292/v2/"}]}, {"id": "v2.4", "status": "SUPPORTED", "links": [{"rel": "self", "href": "http://10.2.0.254:9292/v2/"}]}, {"id": "v2.3", "status": "SUPPORTED", "links": [{"rel": "self", "href": "http://10.2.0.254:9292/v2/"}]}, {"id": "v2.2", "status": "SUPPORTED", "links": [{"rel": "self", "href": "http://10.2.0.254:9292/v2/"}]}, {"id": "v2.1", "status": "SUPPORTED", "links": [{"rel": "self", "href": "http://10.2.0.254:9292/v2/"}]}, {"id": "v2.0", "status": "SUPPORTED", "links": [{"rel": "self", "href": "http://10.2.0.254:9292/v2/"}]}]}


Expected Results:  
glance to return the image list , regardless the version suffix

- Tested in RHOSP16.2.5 and RHOSP16.2.6, curl v2.10 does not return the image list
- Also tested in 17.1.3 and it does work as expected there
- Could it be related to this bug (https://bugzilla.redhat.com/show_bug.cgi?id=2172285), which does not look like is fixed in 16.2.6. In the Glance container, versions.py still show only 2.10 between quotes.