use new URL for callink StudentGroupService

See the thread that was forwarded to sm@ for more info.
Use https://test-studentgroupservice.sait-west.berkeley.edu/service.asmx
for the test version.

ocflib/ucb/groups.py

@@ -9,7 +9,7 @@
 
 
 _API = {
-    'BASE': 'https://saappiis4.sait-west.berkeley.edu/StudentGroupServiceV2/service.asmx',
+    'BASE': 'https://studentgroupservice.sait-west.berkeley.edu/service.asmx',
     'SERVICE': {
         'ORGS': 'CalLinkOrganizations',
         'SIGNATORIES_BY_OID': 'CalLinkGroupSignatories',