[COMMON] Fix condition equality bashisms

pointed out by checkbashisms.

$ mycmd=$(tox -e checkbashisms | grep "(should be 'b = a')" | sed -e
  "s@^[^.]*\(.[^ ]*\) line \([0-9]*\) .*@sed -i -e '\2s/==/=/g' \1;@")

$ eval $mycmd

Issue-ID: OOM-2643
Signed-off-by: Guillaume Lambert <guillaume.lambert@orange.com>
Change-Id: I9032130bc4717e111de11a73187c2f1052376e45
diff --git a/kubernetes/robot/demo-k8s.sh b/kubernetes/robot/demo-k8s.sh
index 5d8fed8..d826888 100755
--- a/kubernetes/robot/demo-k8s.sh
+++ b/kubernetes/robot/demo-k8s.sh
@@ -63,7 +63,7 @@
 
 # Check if execscript flag is used and drop it from input arguments
 
-if [[ "${!#}" == "execscript" ]]; then
+if [[ "${!#}" = "execscript" ]]; then
         set -- "${@:1:$#-1}"
         execscript=true
 fi