Apply belt and suspenders approach and conserve at least some memory in instal monitor process

git-svn-id: https://svn.code.sf.net/p/xcat/code/xcat-core/trunk@10650 8638fb3e-16cb-4fca-ae20-7b5d299a9bcd

xCAT-server/lib/xcat/plugins/dhcp.pm

@@ -2055,6 +2055,8 @@ sub writeout
 		}
 	}
     close($targ);
+    $dhcpconf=(); #dispose of the file contents in memory, no longer needed
+    $aixcfg=();
 
 
     if (@dhcp6conf) {
@@ -2071,6 +2073,7 @@ sub writeout
         print $targ $dhcp6conf[$idx];
     }
     close($targ);
+    @dhcp6conf=();
     }
 }