try to fix coverity bug 'Check of thread-shared field evades lock acquisition'

apollo-client/src/main/java/com/ctrip/framework/apollo/build/ApolloInjector.java

@@ -9,7 +9,7 @@ import com.ctrip.framework.foundation.internals.ServiceBootstrap;
  * @author Jason Song(song_s@ctrip.com)
  */
 public class ApolloInjector {
-  private static Injector s_injector;
+  private static volatile Injector s_injector;
   private static Object lock = new Object();
 
   private static Injector getInjector() {

apollo-core/src/main/java/com/ctrip/framework/foundation/Foundation.java

@@ -13,7 +13,7 @@ public abstract class Foundation {
   private static final Logger logger = LoggerFactory.getLogger(Foundation.class);
   private static Object lock = new Object();
 
-  private static ProviderManager s_manager;
+  private static volatile ProviderManager s_manager;
 
   // Encourage early initialization and fail early if it happens.
   static {