Minor updates for the tools scripts:

* Add ONOS-specific directories to the executable PATH in the envDefaults file
* Fix a typo inside "onos-show-cell": don't show OC0, because it is not used
diff --git a/tools/test/bin/onos-show-cell b/tools/test/bin/onos-show-cell
index 5aee338..d7e56c3 100755
--- a/tools/test/bin/onos-show-cell
+++ b/tools/test/bin/onos-show-cell
@@ -42,7 +42,7 @@
 
 echo "ONOS_CELL=${ONOS_CELL}"
 echo "ONOS_NIC=${ONOS_NIC}"
-for n in {0..9}; do
+for n in {1..9}; do
     ocn="OC${n}"
     if [ -n "${!ocn}" ]; then
         echo "$ocn=${!ocn}"