jenkins: www: Explicitly set ssh username

Change-Id: I3d1f7109dfcec4c41e5386ade04d74fa2a793c0d
diff --git a/jenkins/www/leaf-www.groovy b/jenkins/www/leaf-www.groovy
index 6331e81..65a0526 100644
--- a/jenkins/www/leaf-www.groovy
+++ b/jenkins/www/leaf-www.groovy
@@ -17,9 +17,9 @@
 
                         export MASTER_IP="$(echo $SSH_CLIENT | cut -f1 -d ' ')"
                         export GERRIT_URL="ssh://LeafOS-Jenkins@review.leafos.org:29418/LeafOS-Project/leaf_www"
-                        ssh $MASTER_IP git -C /var/www/leafos.org/ fetch ${GERRIT_URL} ${GERRIT_REFSPEC}
-                        ssh $MASTER_IP git -C /var/www/leafos.org/ reset --hard FETCH_HEAD
-                        ssh $MASTER_IP "cd /var/www/leafos.org; composer install"
+                        ssh jenkins@$MASTER_IP git -C /var/www/leafos.org/ fetch ${GERRIT_URL} ${GERRIT_REFSPEC}
+                        ssh jenkins@$MASTER_IP git -C /var/www/leafos.org/ reset --hard FETCH_HEAD
+                        ssh jenkins@$MASTER_IP "cd /var/www/leafos.org; composer install"
                 '''
             }
         }