title: Removing DB2INSTDEF value from registry
body: <p>Database: DB2 v9.5 on AIX</p>
  
  <p>Scenario: I have 2 instances- db2inst1 and db2inst2. I created db2inst1 first. I went ahead and created db2inst2 next and I do 'db2set -all' on db2inst2 instance I see this:</p>
  
  <p>[g] DB2INSTDEF=db2inst1</p>
  
  <p>I would like to reset DB2INSTDEF and make it not show up when I do 'db2set -all' (other than dropping and recreating db2inst1).</p>
  
  <p>Thanks.</p>