Fix unlikely plStateDescriptor leak

Sources/Plasma/PubUtilLib/plSDL/plSDLMgr.cpp

@@ -187,6 +187,8 @@ int plSDLMgr::Read(hsStream* s, plSDL::DescriptorList* dl)
             plStateDescriptor* sd=new plStateDescriptor;
             if (sd->Read(s))
                 dl->push_back(sd);
+            else
+                delete sd; // well that sucked
         }
     }
     catch(...)