MB-61225: Add error message for max_cas retrieval

Change-Id: I85bd6605cc33a1c2aab7812eafacb1df8421776a
Reviewed-on: https://review.couchbase.org/c/ns_server/+/209428
Tested-by: Navdeep S Boparai <navdeep.boparai@couchbase.com>
Reviewed-by: Steve Watanabe <steve.watanabe@couchbase.com>
Tested-by: Build Bot <build@couchbase.com>

apps/ns_server/src/menelaus_web_buckets.erl

@@ -784,7 +784,8 @@ update_props_with_cas(NodeCasVals, Map, Props) ->
               end, misc:enumerate(Map, 0)),
         {ok, [{vbuckets_max_cas, CasValues} | Props]}
     catch
-        _:_ ->
+        T:E ->
+            ?log_error("Failed to retrieve max_cas: ~p", [{T,E}]),
             {error, max_cas_vbucket_retrieval}
     end.