Add url to the pom for nio and nio-examples (googleapis#909)

* Add url to the pom for nio and nio-examples

To mirror the changes in master.

* Remove already-updated line

Author: jean-philippe-martin

gcloud-java-contrib/gcloud-java-nio-examples/pom.xml

@@ -3,7 +3,8 @@
   <modelVersion>4.0.0</modelVersion>
   <artifactId>gcloud-java-nio-examples</artifactId>
   <packaging>jar</packaging>
-  <name>GCloud Java NIO example</name>
+  <name>GCloud Java NIO examples</name>
+  <url>https://github.com/GoogleCloudPlatform/gcloud-java/tree/master/gcloud-java-contrib/gcloud-java-nio-examples</url>
   <description>
     Demonstrates how to use the gcloud-java-nio jar to add GCS functionality to legacy code.
   </description>

gcloud-java-contrib/gcloud-java-nio/pom.xml

@@ -4,6 +4,7 @@
   <artifactId>gcloud-java-nio</artifactId>
   <packaging>jar</packaging>
   <name>GCloud Java NIO</name>
+  <url>https://github.com/GoogleCloudPlatform/gcloud-java/tree/master/gcloud-java-contrib/gcloud-java-nio</url>
   <description>
     FileSystemProvider for Java NIO to access GCS transparently.
   </description>