Error when ssbStatus is unknown
**Impact of the bug**
WMAgent

**Describe the bug**
ResourceControlUpdater scans the list of site status, if a site is in an "unknown" state it tries to pop a item from ssbStatus (a string) instead of ssbState (a dict).

**How to reproduce it**
Start AgentStatusWatcher with PR #9584 

**Expected behavior**
Pop the item from ssbState instead of ssbStatus.
https://github.com/dmwm/WMCore/blob/2a7ebaaaa108859802a84f73abdce014e3b8e280/src/python/WMComponent/AgentStatusWatcher/ResourceControlUpdater.py#L269

**Additional context and error message**
```
2020-04-02 20:36:57,725:139635865409280:WARNING:ResourceControlUpdater:Site T3_US_PuertoRico has an unknown SSB status 'unknown'. Skipping it!
2020-04-02 20:36:57,725:139635865409280:ERROR:ResourceControlUpdater:Error occurred, will retry later:
2020-04-02 20:36:57,725:139635865409280:ERROR:ResourceControlUpdater:'unicode' object has no attribute 'pop'
2020-04-02 20:36:57,726:139635865409280:ERROR:ResourceControlUpdater:Trace back: 
Traceback (most recent call last):
  File "/data/srv/wmagent/v1.3.0.patch1/sw/slc7_amd64_gcc630/cms/wmagent/1.3.0.patch1/lib/python2.7/site-packages/WMComponent/AgentStatusWatcher/ResourceControlUpdater.py", line 96, in algorithm
    ssbSiteStatus = self.getSiteStatus()
  File "/data/srv/wmagent/v1.3.0.patch1/sw/slc7_amd64_gcc630/cms/wmagent/1.3.0.patch1/lib/python2.7/site-packages/WMComponent/AgentStatusWatcher/ResourceControlUpdater.py", line 271, in getSiteStatus
    ssbStatus.pop(site, None)
AttributeError: 'unicode' object has no attribute 'pop'
```
diff --git a/src/python/WMComponent/AgentStatusWatcher/ResourceControlUpdater.py b/src/python/WMComponent/AgentStatusWatcher/ResourceControlUpdater.py
index 6e3a6eb0a..c70e3b86b 100644
--- a/src/python/WMComponent/AgentStatusWatcher/ResourceControlUpdater.py
+++ b/src/python/WMComponent/AgentStatusWatcher/ResourceControlUpdater.py
@@ -266,7 +266,7 @@ class ResourceControlUpdater(BaseWorkerThread):
             wmcoreStatus = self.getState(str(ssbStatus))
             if not wmcoreStatus:
                 logging.warning("Site %s has an unknown SSB status '%s'. Skipping it!", site, ssbStatus)
-                ssbStatus.pop(site, None)
+                ssbState.pop(site, None)
             else:
                 ssbState[site] = {'state': wmcoreStatus}
 
['src/python/WMComponent/AgentStatusWatcher/ResourceControlUpdater.py']