Force maven version 3.5

CCSDK requires maven version 3.5 or greater, needed by
OpenDaylight Neon release.

Change-Id: I2f696cc14a16ca0992030f6327ba05bb24fd28f8
Issue-ID: CCSDK-1389
Signed-off-by: Timoney, Dan (dt5972) <dtimoney@att.com>
diff --git a/jjb/ccsdk/sli-core.yaml b/jjb/ccsdk/sli-core.yaml
index 3f17f54..2a34eb0 100644
--- a/jjb/ccsdk/sli-core.yaml
+++ b/jjb/ccsdk/sli-core.yaml
@@ -24,6 +24,7 @@
       deployAtEnd=true
     files: '**'
     archive-artifacts: ''
+    maven-version: "mvn35"
     build-node: ubuntu1604-builder-4c-4g
 
 - project:
@@ -38,6 +39,7 @@
     mvn-settings: 'ccsdk-sli-core-settings'
     mvn-goals: 'clean install'
     mvn-opts: '-Xmx1024m -XX:MaxPermSize=256m'
+    maven-version: "mvn35"
 
 - project:
     name: ccsdk-sli-core-clm
@@ -52,6 +54,7 @@
       - 'dublin':
           branch: 'dublin'
     mvn-settings: 'ccsdk-sli-core-settings'
+    maven-version: "mvn35"
     build-node: ubuntu1604-builder-4c-4g