Use github in lieu of gerrit mirror

The gerrit mirror is not always accessible behind corporate firewalls,
thus changed the CSITs to use github instead.
Also modified the script to only clone ci-management to /tmp if it
does not already exist.

Issue-ID: POLICY-3179
Change-Id: I9cac98b04e000d9365e05a1f2ca1c328fef14c6c
Signed-off-by: Jim Hahn <jrh3@att.com>
diff --git a/csit/prepare-csit.sh b/csit/prepare-csit.sh
index 4275841..b15aa4e 100755
--- a/csit/prepare-csit.sh
+++ b/csit/prepare-csit.sh
@@ -33,11 +33,11 @@
 fi
 if [ -f ${ROBOT_VENV}/bin/activate ]; then
     source ${ROBOT_VENV}/bin/activate
-else
+elif [ ! -d /tmp/ci-management ]; then
     rm -rf /tmp/ci-management
     rm -f ${WORKSPACE}/env.properties
     cd /tmp
-    git clone -b master --single-branch git://gerrit-mirror-ap.onap.org/mirror/ci-management.git
+    git clone -b master --single-branch https://github.com/onap/ci-management.git
     source /tmp/ci-management/jjb/integration/include-raw-integration-install-robotframework.sh
 fi