upgrade guava to 16

Author: Justin Richer

openid-connect-common/pom.xml

@@ -51,7 +51,7 @@
  <dependency>
  <groupId>com.google.guava</groupId>
  <artifactId>guava</artifactId>
- <version>14.0.1</version>
+ <version>16.0</version>
  </dependency>
  <dependency>
  <groupId>org.apache.httpcomponents</groupId>