pithos: Clear pithos_public endpoint's versionId

pithos_public service is not an API and should not be versioned; the
public URLs operated by pithos do not include a version segment, anyway.

Also make its type more specific, since type `public' is too generic.

snf-astakos-app/astakos/scripts/snf_service_export.py

@@ -200,12 +200,12 @@ pithos_services = {
     },
 
     'pithos_public': {
-        'type': 'public',
+        'type': 'pithos_public',
         'component': 'pithos',
         'prefix': 'public',
         'public': False,
         'endpoints': [
-            {'versionId': 'v1.0',
+            {'versionId': '',
              'publicURL': None},
         ],
         'resources': {},

snf-pithos-app/pithos/api/services.py

@@ -54,12 +54,12 @@ pithos_services = {
     },
 
     'pithos_public': {
-        'type': 'public',
+        'type': 'pithos_public',
         'component': 'pithos',
         'prefix': 'public',
         'public': False,
         'endpoints': [
-            {'versionId': 'v1.0',
+            {'versionId': '',
              'publicURL': None},
         ],
         'resources': {},