Correctly pass branch env var to Docker
diff --git a/jenkins/build.sh b/jenkins/build.sh
index 00f0256..7f0b098 100755
--- a/jenkins/build.sh
+++ b/jenkins/build.sh
@@ -35,7 +35,7 @@
 cd "$COUCHDB_CI_DIRECTORY"
 
 DOCKER_IMAGE="couchdbdev/"
-DOCKER_OPTIONS="-e $GIT_BRANCH"
+DOCKER_OPTIONS="-e GIT_BRANCH=$GIT_BRANCH"
 
 case $OS in
   centos-6*)