Merge pull request apache#441 from pwendell/graphx-build

GraphX shouldn't list Spark as provided.

I noticed this when building an application against GraphX to audit the released artifacts.
(cherry picked from commit 5fecd25)

Signed-off-by: Patrick Wendell <pwendell@gmail.com>

graphx/pom.xml

@@ -36,7 +36,6 @@
       <groupId>org.apache.spark</groupId>
       <artifactId>spark-core_${scala.binary.version}</artifactId>
       <version>${project.version}</version>
-      <scope>provided</scope>
     </dependency>
     <dependency>
       <groupId>org.eclipse.jetty</groupId>