ICU-1949 another fix for reentrant locks. Better would be a fix to mutex.

X-SVN-Rev: 10217

icu4c/source/common/icuserv.cpp

@@ -822,6 +822,7 @@ ICUService::getKey(Key& key, UnicodeString* actualReturn, const Factory* factory
 #ifdef DEBUG_SERVICE
       fprintf(stderr, "found in service: " + name);
 #endif
+	  if (!factory) umtx_unlock(&ncthis->lock);
       return cloneInstance(result->service);
     }
   }