Fix the pull request branch issues (#274)

.drone.yml

@@ -1,7 +1,6 @@
 ---
 pipeline:
   build:
-    privileged: true
     image: rancher/dind:v0.6.0
     commands:
       - ./scripts/ci

scripts/test

@@ -6,6 +6,10 @@ cd $(dirname $0)/..
 trap "rm -rf /scratch/*" exit
 
 GIT_BRANCH=$(git rev-parse --abbrev-ref HEAD)
+if [ -n "${DRONE_BRANCH}" ]; then
+    git checkout -b ${DRONE_BRANCH}
+    GIT_BRANCH=${DRONE_BRANCH}
+fi
 
 if [ "$GIT_BRANCH" != "master" ]; then
   sed -i "s#master#$GIT_BRANCH#" ./scripts/repo.json