Add support for using postgresql.

This adds a new condition to enable postgresql in devstack.
This will allow for periodic testing of tempest with either
mysql or postgresql.

Change-Id: I1849d1cd0d03d9911e6cd9973a9d9f960f30e91a

devstack-vm-gate-wrap.sh

@@ -24,6 +24,9 @@ PROJECTS="openstack-dev/devstack openstack/nova openstack/glance openstack/keyst
 # Set to 1 to run the Tempest test suite
 export DEVSTACK_GATE_TEMPEST=${DEVSTACK_GATE_TEMPEST:-0}
 
+# Set to 1 to run postgresql instead of mysql
+export DEVSTACK_GATE_POSTGRES=${DEVSTACK_GATE_POSTGRES:-0}
+
 # Set to 1 to run cinder instead of nova volume
 # Only applicable to stable/folsom branch
 export DEVSTACK_GATE_CINDER=${DEVSTACK_GATE_CINDER:-0}

devstack-vm-gate.sh

@@ -95,6 +95,12 @@ if [ "$DEVSTACK_CINDER_SECURE_DELETE" -eq "0" ]; then
    cat <<\EOF >>localrc
 CINDER_SECURE_DELETE=False
 EOF
+fi
+
+if [ "$DEVSTACK_GATE_POSTGRES" -eq "1" ]; then
+        cat <<\EOF >>localrc
+use_database postgresql
+EOF
 fi
 
    cat <<EOF >>exerciserc