java - Tomcat: Changes made to tomcat-users.xml got undone -

i faching strange problem. on opensuse linux environment, have edited following file in order ant script working tomcat7:

/tomcat_home/conf/tomcat-users.xml 

i have edited following:

<role rolename="manager-script"/> <role rolename="manager-gui"/>  <user username="tomcat" password="admin" roles="manager-gui, manager-script"/> 

the strange part have made these days ago, , cannot see these changes in above mentioned file.

do these changes undone when machine/tomcat restarts?

my ant script seems working fine still, if above changes undone why ant script still running.

yes, have looked file root user well.

any idea, happenng here?