global-defaults: Remove jdk global version

This global version of JDK was added as part of the
Maven block after re-using code from another project.

Change-Id: Iff2eb13405b85b22aa4e9ab15db0f3cda6ba6026
Signed-off-by: Jessica Wagantall <jwagantall@linuxfoundation.org>
diff --git a/jjb/global-defaults.yaml b/jjb/global-defaults.yaml
index aaeec9b..9dd302f 100644
--- a/jjb/global-defaults.yaml
+++ b/jjb/global-defaults.yaml
@@ -14,8 +14,7 @@
     # default gerrit server definition
     server-name: 'Primary'
 
-    # Maven / Java
-    jdk: 'openjdk8'
+    # Maven
     onap-infra-mvn-opts: |
         --show-version
         --batch-mode