Fix syntax error on the common script

Signed-off-by: Borja Clemente <[email protected]>

Author: clebs

deploy/common.sh

@@ -8,12 +8,12 @@ readonly KUBECTL="${GCE_PD_KUBECTL:-kubectl}"
 # Common functions
 
 function ensure_var(){
-    if [[ -v "${1}" ]];
+    if [[ -z "${!1}" ]];
     then
-        echo "${1} is ${!1}"
-    else
         echo "${1} is unset"
         exit 1
+    else
+        echo "${1} is ${!1}"
     fi
 }