nfs: make spring dependency scope provided

Motivation:
as nfs-spring module expected to be used in spring based application,
we can expect spring libraries to be available at the runtime.

Modification:A
make spring dependency scope `provided`

Result:
less mess with transient dependencies for spring based apps.

Acked-by: Lea Morschel
Acked-by: Paul Millar
Target: master

spring/pom.xml

@@ -17,6 +17,7 @@
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-context</artifactId>
+            <scope>provided</scope>
         </dependency>
         <dependency>
             <groupId>org.dcache</groupId>