Duplicate record is written in property file when group name set to empty

Duplicate records are registered in mgmt-groups.properties and application-roles.properties if adding user with empty group name as follows.

1. Add user "testuser1" with empty group from add-user.sh.
$JBOSS_HOME/bin/add-user.sh -sc ./standalone/configuration -u testuser1 -p RedHat1! -g ""

2. After that, the following record is written in the group property file.

• mgmt-groups.properties (application-roles.properties)
  testuser1=

3. Add user "testuser2" with empty group from add-user.sh.
$JBOSS_HOME/bin/add-user.sh -sc ./standalone/configuration -u testuser2 -p RedHat1! -g ""

4. After that, the user records that have empty group will be registered duplicately as below.

• mgmt-groups.properties (application-roles.properties)
  testuser1=
  testuser2=
  testuser1= # duplicate record