swap optional and scope as previous commit

Author: guohao

contrib/grpc-spring/pom.xml

@@ -41,8 +41,8 @@
             <groupId>javax.servlet</groupId>
             <artifactId>servlet-api</artifactId>
             <version>2.5</version>
-            <optional>true</optional>
             <scope>provided</scope>
+            <optional>true</optional>
         </dependency>
         <dependency>
             <groupId>io.grpc</groupId>