HPCC-18301 Memory leaks in ldapsecurity dll when authorizing a user

Resource permission cache was not release a map entry, resulting in a leak.
This PR releases that object before erasing to object that references it

Signed-off-by: Russ Whitehead <william.whitehead@lexisnexis.com>

system/security/shared/caching.cpp

@@ -158,6 +158,7 @@ void CResPermissionsCache::add( IArrayOf<ISecResource>& resources )
                     break;
                 }
             }
+            resParamCacheEntry.second->Release();
             m_resAccessMap.erase(SecCacheKeyEntry(resource, resourcetype));
         }
 #ifdef _DEBUG