use managed guava version

Change-Id: I470f69999259ef1233bf37fbc55920b9bd151c7e
diff --git a/web/api/pom.xml b/web/api/pom.xml
index 11d90cc..e6f9ff8 100644
--- a/web/api/pom.xml
+++ b/web/api/pom.xml
@@ -26,7 +26,6 @@
         <dependency>
             <groupId>com.google.guava</groupId>
             <artifactId>guava</artifactId>
-            <version>17.0</version>
             <scope>test</scope>
         </dependency>