Set the hostname properly on the machine and rejoin or alternatively you can join using the -n option.
-n computer Specify name of computer object
This allows you to specify the name used during the join. Addition and join options can be seen by running the following on a machine with QAS installed.
/opt/quest/bin/vastool join
Usage: vastool join [-flwUG] [-I filename] [-h string] [-n computer] [-c container] [-r string] [-u string] [-g string] [-s string] [-p string] [--skip-config]
[--preload-nested-memberships] [--site-only-usn] [--site-only-servers] [--no-timesync] [--autogen-posix-attrs] domain_name [domain_controllers]
-I filename Load cache from specified quickstart cache export file instead
of from the network.
-n computer Specify name of computer object
-c container LDAP DN of the container where the computer will be created
-f Overwrite existing computer object
-l Don't apply Group Policy Settings (if Group Policy is installed)
-w Enable workstation mode - users will not be cached until they
login
-U Load all users from the global catalog
-G Load all groups from the global catalog
-r string Comma-separated list of alternate authentication domains
-u string Specify an alternate search path from which to populate the
users cache
-g string Specify an alternate search path from which to populate the
groups caches
-s string Specify the site name for this machine
-p string Specify the path of the Primary Personality Container
--skip-config Skip automatic configuration of PAM, NSS, LAM and SIA
--preload-nested-memberships After loading users and/or groups, query tokenGroups for all cached users
--site-only-usn Deprecated, use the "site-only-servers" option.
--site-only-servers Restricts all LDAP searches to servers servers in this machine's site (no out of site failover).
--no-timesync Skip automatic time synchronization
--autogen-posix-attrs Enable auto generation of Posix IDS for Active Directory Users