jenkins: www: Use pull instead of reset --hard

* To prevent older changes from messing up if the job picks up newer ones first

Change-Id: Iada53705fc3c3a27df388fa8e3675d7e47cc5ff0
diff --git a/jenkins/www/leaf-www.groovy b/jenkins/www/leaf-www.groovy
index 65a0526..0b138c6 100644
--- a/jenkins/www/leaf-www.groovy
+++ b/jenkins/www/leaf-www.groovy
@@ -17,8 +17,8 @@
 
                         export MASTER_IP="$(echo $SSH_CLIENT | cut -f1 -d ' ')"
                         export GERRIT_URL="ssh://LeafOS-Jenkins@review.leafos.org:29418/LeafOS-Project/leaf_www"
-                        ssh jenkins@$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@$MASTER_IP git -C /var/www/leafos.org/ reset --hard
+                        ssh jenkins@$MASTER_IP git -C /var/www/leafos.org/ pull ${GERRIT_URL} ${GERRIT_REFSPEC}
                         ssh jenkins@$MASTER_IP "cd /var/www/leafos.org; composer install"
                 '''
             }