Minor fix: fail when tox not passes

Also, add the exporters to the list of charms tested by the stage-test
script

Change-Id: Ibb5e4d5ff057a517386384633d6829b8b84252ce
Signed-off-by: David Garcia <david.garcia@canonical.com>

devops-stages/stage-test.sh

@@ -18,10 +18,9 @@ CURRENT_DIR=`pwd`
 
 # Execute tests for charms
 CHARM_PATH="./installers/charm"
-CHARM_NAMES="keystone lcm mon nbi ng-ui pla pol prometheus ro grafana"
+CHARM_NAMES="keystone lcm mon nbi ng-ui pla pol prometheus ro grafana mongodb-exporter mysqld-exporter kafka-exporter"
 for charm in $CHARM_NAMES; do
     cd $CHARM_PATH/$charm
-    OUTPUT=$(TOX_PARALLEL_NO_SPINNER=1 tox --parallel=auto)
-    printf "$OUTPUT\n"
+    TOX_PARALLEL_NO_SPINNER=1 tox --parallel=auto
     cd $CURRENT_DIR
 done
\ No newline at end of file