Failure of adgentns.pl During Adcfgclone.pl 

During cloning of our EBS 12.1.1 env when running adcfgclone.pl on DB Tier we hit following error.
adconfig.log
[CVM Error Report]
The following report lists errors encountered during CVM Phase
      <filename>  <return code where appropriate>
  /u01/app/oracle/visr12/apps/apps_st/appl/ad/12.0.0/bin/adgentns.pl  2
No of scripts failed in CVM phase: 1
AutoConfig is exiting with status 1

NetServiceHandler.log
ORA-12154: TNS:could not resolve the connect identifier specified
Unable to generate listener.ora from database Using default listener.ora file
.end std out.
.end err out.
Error while generating listener.ora.
StackTrace:
java.lang.Exception: Error while generating listener.ora. at oracle.apps.ad.tools.configuration.NetServiceHandler.generateMiddleTierListener(NetServiceHandler.java:2495) at oracle.apps.ad.tools.configuration.NetServiceHandler.processNode(NetServiceHandler.java:2269)
        at oracle.apps.ad.tools.configuration.NetServiceHandler.main(NetServiceHandler.java:3010)
Closing connection
Connection Closed

During trouble shooting we figured out that the DB was being started but listener was not able to hand off the connection to DB coz the listener generation using adgentns.pl was failing. 
So as a work around I removed the ../network/admin folder from ORACLE_HOME (which was copied from source) and started the default listener on 1521. Since the failure was running during running AutoConfig in cloning, I ran AutoConfig manually on DB Tier and it went nicely this time around. 

[oracle@apps_rac01 bin]$ ./adconfig.sh 

Enter the full path to the Context file: ../visr12_apps_rac01.xml

Enter the APPS user password: 

The log file for this session is located at: /u01/app/oracle/product/11.2.0/db_1/appsutil/log/visr12_apps_rac01/07200357/adconfig.log

AutoConfig is configuring the Database environment...

AutoConfig will consider the custom templates if present.

        Using ORACLE_HOME location : /u01/app/oracle/product/11.2.0/db_1

        Classpath                   : :/u01/app/oracle/product/11.2.0/db_1/jdbc/lib/ojdbc5.jar:/u01/app/oracle/product/11.2.0/db_1/appsutil/java/xmlparserv2.jar:/u01/app/oracle/product/11.2.0/db_1/appsutil/java:/u01/app/oracle/product/11.2.0/db_1/jlib/netcfg.jar:/u01/app/oracle/product/11.2.0/db_1/jlib/ldapjclnt11.jar

        Using Context file          : /u01/app/oracle/product/11.2.0/db_1/appsutil/visr12_apps_rac01.xml

Context Value Management will now update the Context file

        Updating Context file...COMPLETED

        Attempting upload of Context file and templates to database...COMPLETED

Updating rdbms version in Context file to db112

Updating rdbms type in Context file to 32 bits

Configuring templates from ORACLE_HOME ...

AutoConfig completed successfully.

On DB Node - 
SQL> sho parameter db_name

NAME                                 TYPE        VALUE

------------------------------------ ----------- ------------------------------

db_name                              string      visr12

SQL> sho user

USER is "APPS"

SQL> exec fnd_conc_clone.setup_clean;

PL/SQL procedure successfully completed.