How to change parameter - perm.violation.title

Hi Atlassian,

Let me start that we are in the process of upgrading to JIRA 7.3.

We would like to edit some parameter on this properties file in our current JIRA (6.4.12):
JiraWebActionSupport.properties

this is the line we want to edit:
perm.violation.desc = It seems that you have tried to perform an operation which you are not permitted to perform.

I’ve edit it to :
perm.violation.desc = It seems that you have tried to perform an operation which you are not permitted to perform please contact the us via IT Portal.

Saved the file and restart the JIRA service, I logged into our JIRA and no change was made.
what am I doing wrong ?