Sessions: Drop end / from odata.id

Fix warnings around odata.id not matching. Was looking at old defects,
and closed https://github.com/openbmc/bmcweb/issues/166 (closed since no
longer see these warnings) but saw we have these warnings for sessions:

```
*** /redfish/v1/SessionService
Attempt 1 of /redfish/v1/SessionService
Response Time for GET to /redfish/v1/SessionService: 0.046112860552966595 seconds.
/redfish/v1/SessionService @odata.id: Expected @odata.id to match URI link /redfish/v1/SessionService/
    Type (SessionService.v1_0_2.SessionService), GET SUCCESS (time: 0:00:00.046476)
Attempt 1 of /redfish/v1/SessionService/Sessions
Response Time for GET to /redfish/v1/SessionService/Sessions: 0.005822769366204739 seconds.
    PASS

*** /redfish/v1/SessionService/Sessions
/redfish/v1/SessionService/Sessions @odata.id: Expected @odata.id to match URI link /redfish/v1/SessionService/Sessions/
    Type (SessionCollection.SessionCollection), GET SUCCESS (time: 0:00:00.006165)
```

It looks like all other odata.ids don't end in a /
https://github.com/search?q=repo%3Aopenbmc%2Fbmcweb%20odata.id&type=code

Tested: NONE. Visual inspection only.
Signed-off-by: Gunnar Mills <gmills@us.ibm.com>
Change-Id: Ie1cde192a5774a86c96e6993c71e8b124c79739a
diff --git a/redfish-core/lib/redfish_sessions.hpp b/redfish-core/lib/redfish_sessions.hpp
index 7061c9a..3971791 100644
--- a/redfish-core/lib/redfish_sessions.hpp
+++ b/redfish-core/lib/redfish_sessions.hpp
@@ -172,7 +172,7 @@
     asyncResp->res.jsonValue["@odata.type"] =
         "#SessionCollection.SessionCollection";
     asyncResp->res.jsonValue["@odata.id"] =
-        "/redfish/v1/SessionService/Sessions/";
+        "/redfish/v1/SessionService/Sessions";
     asyncResp->res.jsonValue["Name"] = "Session Collection";
     asyncResp->res.jsonValue["Description"] = "Session Collection";
 }
@@ -282,7 +282,7 @@
 
     asyncResp->res.jsonValue["@odata.type"] =
         "#SessionService.v1_0_2.SessionService";
-    asyncResp->res.jsonValue["@odata.id"] = "/redfish/v1/SessionService/";
+    asyncResp->res.jsonValue["@odata.id"] = "/redfish/v1/SessionService";
     asyncResp->res.jsonValue["Name"] = "Session Service";
     asyncResp->res.jsonValue["Id"] = "SessionService";
     asyncResp->res.jsonValue["Description"] = "Session Service";