Fix experimental trove-image-build gate job

Fixed the experimental trove-image-build gate job to:
- Use /opt/trove-image-build instead of /opt/stack to avoid confusion
  with dvm-gate jobs.
- Export the right value for KEY_DIR
- Copy the built image to the correct location on tarballs.o.o

Change-Id: Idc1ea86fe7c692f318d5c6b004f73c10293d4607

modules/openstack_project/files/jenkins_job_builder/config/trove-images.yaml

@@ -8,9 +8,10 @@
       - gerrit-git-prep
       - shell: |
           #!/bin/bash -xe
-          sudo mkdir -p /opt/stack
-          sudo chown $(whoami) /opt/stack
-          export DEST=/opt/stack
+          sudo mkdir -p /opt/trove-image-build
+          sudo chown $(whoami) /opt/trove-image-build
+          export DEST=/opt/trove-image-build
+          export KEY_DIR=`pwd`/files/keys
           cd scripts
           ./redstack build-image mysql
           mv $HOME/images/ubuntu_mysql/ubuntu_mysql.qcow2 $WORKSPACE/ubuntu_mysql.qcow2
@@ -20,7 +21,7 @@
           site: 'tarballs.openstack.org'
           files:
             - source: 'ubuntu_mysql.qcow2'
-              target: 'trove/images/ubuntu_mysql.qcow2'
+              target: 'tarballs/trove/images/ubuntu_mysql.qcow2'
               keep-hierarchy: false
               copy-after-failure: false
       - console-log